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Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-18T02:49:02Z

KemingWu: /* Conclusion */

==Introduction to Petroleum Systems==

Oil and natural gas are among the most important geological resources utilized by modern society. This industry fuels the global economy and energy is used for electricity, transportation, and industrial manufacturing. The oil and gas industry is considered in three main sectors<ref name=":3">{{Cite web|last=McClay|first=R.|date=2025-10-12|title=Understanding the Oil and Gas Industry: A Comprehensive Overview|url=https://www.investopedia.com/investing/oil-gas-industry-overview/|url-status=live|website=Investopedia}}</ref>:
{| class="wikitable"
|'''Upstream Sector'''
|'''Midstream Sector'''
|'''Downstream Sector'''
|-
|Include exploration and production. Companies drill for oil and gas.
|Include transportation and usage. Companies handle transit to oil refineries.
|Include refining and distribution. Companies produce refined oil and gas and sell it as gasoline and jet fuel.
|}
Oil and gas consists of hydrocarbons that form naturally within Earth’s crust over millions of years. Organic material derived from plants, animals, and microbes accumulate within depositions, and over geological time, become incorporated into sedimentary rocks. These rocks include sandstone, limestone, and shale, and form in ancient oceans. Burial beneath additional sediment subjects organic matter to high temperatures and pressures, leading to the formation of oil and natural gas within the subsurface<ref name=":3" />.

Hydrocarbons may migrate through porous and permeable sedimentary rocks, as they are less dense than surrounding water. An oil and gas reservoir is created when migrating hydrocarbons reach a barrier. These are the types of reservoirs that are used by the petroleum industry, obtained by drilling through overlying rocks into the subsurface<ref name=":3" />.

The geological formation of oil and gas, including the essential elements and processes, describe the way that hydrocarbons accumulate within the Earth's subsurface. In order for a reservoir to be viable, it must also demonstrate certain qualities, including porosity and permeability, that support hydrocarbon storage. The oil exploration and extraction demonstrate how geology contributes to the modern reservoir locating and guiding to production. Some technologies including seismic surveys and reservoir simulations also been introduced to demonstrate the importance of geological information to engineering decisions. The environmental issues from the oil and gas industry, including onshore induced seismicity and offshore ecological threats, must be carefully monitored throughout all stages of exploration, extraction, and production. To control these impacts, geologists and engineers take responsibility for introducing seismic monitoring techniques and protective restrictions.

The petroleum industry is closely related to chemistry and engineering. Geology identifies the source rocks, reservoirs, seals, and migration pathways required for hydrocarbon accumulation. Chemistry helps to explain the transformation into petroleum under changing pressure and temperatures. This influences engineering decisions related to exploration, production, and resource development. Petroleum systems demonstrate how geological processes create conditions for both chemical and engineering applications.

== Geological Formation ==
The occurrence of oil and gas within the Earth’s crust is demonstrated by a geological framework known as the Total Petroleum System<ref name=":4">{{Cite journal|last=Magoon|first=L. B.|last2=Schmoker|first2=J. W.|date=2000|title=The Total Petroleum System - The Natural Fluid Network that Constrains the Assessment Unit|url=https://pubs.usgs.gov/dds/dds-060/chaps/PS.pdf|journal=United States Geological Survey|pages=1-20}}</ref>. This is the basis for assessing hydrocarbon resources, as it considers both geological elements and processes required for the accumulations to exist. A petroleum system consists of four essential geological elements; source rock, reservoir rock, seal rock, and overburden rock. Together with these elements, the essential processes of the Total Petroleum System are generation, migration, accumulation, and trap formation. The first stage of oil and gas formation is hydrocarbon generation within a source rock, defined as the origin of petroleum within the system. The “pod of active source rock” are adjacent source rocks that are responsible for generating hydrocarbons. Under high temperature and pressure conditions, hydrocarbons are expelled from the source rock and into surrounding rocks<ref name=":4" />.

Once generated, hydrocarbons migrate through the subsurface. A petroleum system requires pathways that allow the oil and gas to move from the source rock and into geological formations that can store hydrocarbons. Without migration pathways, generated hydrocarbons would remain trapped within the source rock and accumulations would not form<ref name=":4" />.
[[File:Figure 1. Geological Cross-Section of an OIl and Gas Reservoir.png|thumb|514x514px|Figure 1. Geological Cross-Section of an Oil and Gas Reservoir]]
Hydrocarbons accumulate within the pores of reservoir rocks. Reservoir rocks are essential to the petroleum system since they provide space for hydrocarbon storage. Reservoir characterization studies evaluate properties including porosity and permeability; qualities that dictate the amount of available hydrocarbon storage as well as the ease that fluid can move within the rock. Reservoir rocks with high porosity and permeability are considered more effective at storing hydrocarbons<ref name=":5" />.

For hydrocarbons to remain within a reservoir, a seal rock must also be present. Seal rocks are identified as one of the four essential petroleum system elements because they act as barriers that restrict fluid movement and prevent hydrocarbons from escaping. Additionally, trap formation must occur to retain migrating hydrocarbons. The process of accumulation and trap formation are together required to create and preserve petroleum deposits<ref name=":4" />.

The final essential element of a petroleum system is overburden rock. Overburden refers to the layers of sediment and rock that accumulate above the source rock and reservoir rock over geological time. As additional sediments are deposited, the increasing thickness of overburden subjects underlying rocks to higher temperatures and processes during burial. These conditions influence the thermal maturity of source rocks and play a crucial role in hydrocarbon generation. Therefore, the thickness and burial history over the overburden can be used by geologists to determine whether or not the source rocks have reached the temperature and pressure conditions that are necessary for oil and gas formation<ref name=":4" />.

== Reservoir Quality ==

The presence of a petroleum system alone does not always guarantee that hydrocarbons can be recovered economically. Reservoir quality is primarily determined by porosity and permeability, which are considered the fundamental factors of the petroleum reservoir viability. Porosity refers to the amount of pore space available within a rock for hydrocarbon storage, while permeability describes the degree to which fluids can move through connected pore networks. Reservoir rocks may contain significant pore space but still be considered poor-quality if pore connections are limited. Consequently, both properties must be evaluated when assessing whether or not a reservoir is considered commercially viable. Other important factors of reservoir quality include depositional environment, sediment provenance, weathering, compaction, dissolution, burial depth, pressure, and structural deformation. Since these controls interact over millions of years, reservoir quality reflects cumulative effects, from the time of sediment deposition<ref name=":5" />.

One of the most important controls on reservoir quality is the depositional environment in which the sediment was originally deposited. The primary composition of sediment strongly influences the future evolution of reservoir rocks. In sandstone reservoirs, factors such as the source-area geology, climate, topography, and grain size all affect the resulting rock properties. These factors all influence pore space, and therefore impact reservoir quality. Sediments deposited in shallow marine environments often develop better reservoir properties because they tend to be cleaner and contain fewer fine materials that can reduce pore connections. On the other hand, sediments deposited in low-energy environments may contain more clay and silt, which can negatively affect reservoir quality. Well-sorted sediments generally have more interconnected pores than poorly sorted sediments that contain fine grain matrix material<ref name=":5" />.

Different lithologies also respond differently to geological processes. Sandstone reservoirs are among the most common hydrocarbon reservoirs because they can preserve great porosity between sediment grains. Carbonate reservoirs, including limestone and dolostone, often undergo many diagenetic changes through processes such as dissolution, recrystallization, and dolomitization due to their greater chemical reactivity. Rather than relying solely on primary pore space, carbonate reservoirs often develop secondary porosity through diagenesis and fracturing. As a result, both sandstone and carbonate reservoirs often have the capacity to contain hydrocarbons, although having very different pore systems and geological histories<ref name=":5" />.

Following deposition, sediment undergoes diagenesis when physical and chemical changes occur as the sediment is transformed into sedimentary rock. Important stages in reservoir evolution include eodiagenesis (early burial diagenesis), mesodiagenesis (burial diagenesis), and telodiagenesis (uplift-related changes)<ref name=":5" />. During these stages, sediments experience compaction, dissolution, mineral replacement, fracturing, and fluid interactions that can significantly alter reservoir properties. These diagenetic processes can reduce reservoir quality. Compaction during burial decreases pore space as sediment gains become more tightly packed. Chemical compaction and pressure solution may further reduce porosity. Minerals such as quartz, calcite, dolomite, and clay can fill pore spaces and restrict fluid movement. Quartz cementation is identified as one of the most important pore-filling processes in deep buried sandstone reservoirs because of the way it reduces the amount of available pore space progressively. Clay mineral does so similarly and may significantly decrease permeability by blocking pores and restricting fluid flow <ref name=":5">{{Cite journal|last=Worden|first=R. H.|last2=Armitage|first2=P. J.|last3=Butcher|first3=A. R.|last4=Churchill|first4=J. M.|last5=Csoma|first5=A. E.|last6=Hollis|first6=C.|last7=Lander|first7=R. H.|last8=Omma|first8=J. E.|date=2018|title=Petroleum reservoir quality prediction: overview and contrasting approaches from sandstone and carbonate communities|url=https://doi.org/10.1144/SP435.21|journal=Geological Society|volume=435|pages=1-31}}</ref>.

Reservoir quality is not solely determined by burial and porosity. The final characteristics of a reservoir are reflected by the preservation of the pore space. Reservoirs with similar depositional origination may exhibit very different porosity and permeability depending on their diagenetic history and the geological conditions they experienced during burial and uplift<ref name=":5" />.
== Oil and Gas Exploration: Seismic Technology ==

Now we know the formation of oil and gas, the next question is where to locate them. Since reservoirs are below the surface, geologists cannot directly see where they are before drilling. This makes drilling a gamble, and that's where seismic reflection technology contributes to lowering the risk. It works as a tool that helps geologists to create an image of what is beneath the surface before they decide where to drill <ref name=":0">{{Cite journal|last=Mohammed|first=Farfour|date=2016-05-01|title=A review on multicomponent seismology: A potential seismic application for reservoir characterization|url=https://www.sciencedirect.com/science/article/pii/S2090123215001125|journal=Journal of Advanced Research|volume=3|pages=515-524}}</ref>.[[File:Seismic_Survey_and_Mechanism.png|thumb|left|500x500px|Figure 1. Seismic Technology and Mechanism for oil Exploration]]The working principle behind seismic is to use energy waves to explore underground rock layers. During a survey, energy waves are sent into the ground. When waves hit the boundaries between rock layers, some of the energy bounces back to the surface, while some goes further. Receivers then pick up these reflected waves and give information about the depth, shape and arrangement of subsurface layers by analyzing the different waves using the pre-known typical rock’s density and acoustic impedance. After processing, the data can be shown as profiles or 3D seismic images <ref>{{Cite journal|last=Ilya|first=Tsvankin|date=2010-09-01|title=Seismic anisotropy in exploration and reservoir characterization: An overview|url=https://www.researchgate.net/publication/228633261_Seismic_anisotropy_in_exploration_and_reservoir_characterization_An_overview|journal=Geophysics|volume=75}}</ref>.

This is essential because oil and gas need geological structures to build up, and seismic interpretation helps identify these structures. For example, folds show up as layers in seismic images. If the fold creates an anticline, oil and gas might move upward and get trapped near the top. Faults can be spotted when rock layers are broken or displaced. Faults can create traps but might let hydrocarbons escape if they aren't sealed properly. Therefore, seismic data is not just used to "find oil", it helps us understand if subsurface geology has the right structure to store oil and gas<ref>{{Cite journal|last=Lawson|first=M.|date=2018-02-19|title=Geochemical applications in petroleum systems analysis: New constraints and the power of integration|url=https://www.researchgate.net/publication/323282762_Geochemical_applications_in_petroleum_systems_analysis_New_constraints_and_the_power_of_integration|journal=Geological Society, London, Special Publications|volume=468|pages=6}}</ref> . Beyond locating the reservoir, seismic technology also helps geologists understand the environmental geometry. This includes the shape, thickness, depth and continuity of a reservoir. This matters because a reservoir can be located but not profitable for business. With current technology and the purpose of maximizing the future extraction, geologists are targeting large and continuous reservoirs rather than thin and isolated ones. Seismic data can help pinpoint the drilling target by showing where the reservoir may be thicker or larger<ref name=":0" /> .

An exploration workflow usually starts with a regional study. The first step is for geologists to determine if the region has a petroleum system with possible traps that contain oil. Next, follow-up seismic surveys help to collect evidence and more information. Further, geoscientists interpret the data to distinguish geological structures and possible drilling targets. These decisions are assisted by other data, such as core samples <ref name=":1">{{Cite journal|last=Ma|first=Yuan Zhe|date=2011-01-01|title=Uncertainty Analysis in Reservoir Characterization and Management: How Much Should We Know About What We Don't Know?|url=https://pubs.geoscienceworld.org/aapg/books/edited-volume/1248/chapter-abstract/107059711/Uncertainty-Analysis-in-Reservoir-Characterization?redirectedFrom=fulltext|journal=AAPG Memoir|volume=1|pages=15}}</ref>.

However, seismic technology is not perfect. As an imaging technique that relies on the reflection of waves, some thin reservoirs or structures can be hard to detect. Also, seismic data cannot directly show the oil and gas but uses structures to infer their existence. Based on this limitation, seismic technology is more like a tool that reduces drilling risk than eliminates all uncertainties <ref>Saad, M. R., & Jadeer, A.-S. (2022). ''Seismic Method for Exploration Oil and Gas Reservoirs''. <nowiki>https://doi.org/10.1007/978-981-99-1964-2_89</nowiki></ref>.

== Oil and Gas Extraction: How Geology Determines Engineering Decisions ==
Once an oil reservoir is proven as continuous and profitable, geology still plays a role in deciding how to extract the resources. In practice, engineering decisions and extraction methods are based on how the subsurface is structured and how fluids move through the rock.

Engineers need further geological information before deciding where to drill. They need to know the depth of the potential drilling trajectory, the thickness of the oil reservoir, and the fluid contacts of the reservoir to optimize the performance. For example, a rich oil-bearing zone in the reservoir should be the highest priority to place the well nearby. However, if the zone is disrupted by some faults, then engineers and geologists must determine whether these faults connect to parts of the reservoir or cut it into separate parts. Moreover, if the production well is too close to a water or gas zone, a water or gas breakthrough is likely to happen and reduce oil production. In a real-world case, a breakthrough can easily turn a high-production well into a shut-down.
[[File:Reservori_Simulation_Model.jpg|thumb|Figure 2. The reservoir modeling workflow showing the sequence of stages in data acquisition and interpretation<ref name=":2">Abel, M., Garcia, L., Lorenzatti, A., & De Ros, L. (2010, October 26). ''SEMANTIC INTEROPERABILITY IN THE PETROLEUM CHAIN: THE CONTRIBUTION OF ONTOLOGICAL ANALYSIS''.</ref>|549x549px]]Reservoir simulation is a great tool to use in oil extraction, just like how seismic technology assists oil exploration. A reservoir model is a digital version of a reservoir with a vivid representation of reservoir structures and various relevant properties like pressure, permeability, porosity, and saturation of each phase. Engineers use this model to predict how the reservoir might behave during production. For instance, the model can estimate production rates, pressure changes, and any potential water cut. It can also achieve optimization on certain jobs, like comparing different production plans and well placement strategies. Since the model is built purely based on geological data, its quality varies depending on how well the regional geology is captured and understood, and this can also be a limitation of the reservoir model <ref name=":2" /><ref>Sambo, C., Iferobia, C. C., Babasafari, A. A., Rezaei, S., & Akanni, O. A. (2020). The Role of Time Lapse(4D) Seismic Technology as Reservoir Monitoring and Surveillance Tool: A Comprehensive Review. ''Journal of Natural Gas Science and Engineering'', ''80'', 103312. <nowiki>https://doi.org/10.1016/j.jngse.2020.103312</nowiki></ref>.

Since there are many different types of reservoirs, extraction methods have also been developed differently to achieve efficient production for each case. And they can be separated under two main reservoir types: conventional and unconventional.
{| class="wikitable"
|+
!Reservoir Type
!Geological Characteristics
!Main Extraction Methods
!Engineering
Reason
|-
|Conventional reservoirs
|High permeability and porosity for fluids to flow naturally toward the well through connected pore spaces
|Primary production relies on natural reservoir pressure and secondary recovery methods like water injection are used to maintain the pressure
|Maintain and increase reservoir pressure to improve flow toward production wells
|-
|Unconventional reservoirs
|Low permeability so fluids are trapped in rocks or exist as highly viscous bitumen
|Horizontal drilling and hydraulic fracturing are commonly used for shale gas and tight oil
For deep oil sands, steam-assisted gravity drainage can be used by injecting steam underground to heat bitumen and lower the viscousity
|Create flow pathways to make hydrocarbons mobile enough to be produced
|}
Overall, geology has a strong influence on engineering decisions in oil and gas extraction. Geology informs engineers to know the reservoir quality, what extraction methodology can be applied, and what risks might exist during production. Geological information has also been integrated into reservoir models to provide a more in-depth understanding and optimization. Oil extraction is not just about improving equipment and technology, it is also a process in which geological knowledge is applied with engineering decisions.

== Chemical Engineering and Petroleum Products ==
[[File:Fractional Distillation.jpg|thumb|Fractional Distillation Process of Crude Oil<ref>[https://wigmoretrading.com/what-is-the-fractional-distillation-process-of-oil-in-nigeria/]</ref>|512x512px]]
Crude oil, in its unrefined state, has almost no direct utility due to its highly complex molecular constitution. It exists fundamentally as a dense, complex mixture of hundreds of different hydrocarbons. The three basic components of crude oil are alkanes, cycloalkanes, and aromatics. The primary steps of chemical engineering within petroleum refineries are physical separation and chemical conversion. The first step separates the heterogeneous mixture into narrower, manageable fractions based on physical properties, and the second step upgrades these fractions into high-value, commercially viable products. This transformation from raw, unusable crude oil into high-value fuels relies on a sequence of thermal processes and complex catalytic reactions that manipulate molecular structures.<ref name=":6">Gary, J.H., Handwerk, J.H., Kaiser, M.J., & Geddes, D. (2007). Petroleum Refining: Technology and Economics, Fifth Edition (5th ed.). CRC Press. <nowiki>https://doi.org/10.4324/9780203907924</nowiki></ref>

The foundational stage of any refinery configuration is fractional distillation. The process depends on the differential volatility and boiling points of the constituent hydrocarbons within crude oil. Fractional distillation is commonly operationalized through the Atmospheric Distillation Unit, and crude oil is preheated to approximately 350-400°C, then pumped into the lowest and hottest level in the fractional distillation tower. As the vaporized oil ascends through a series of distillation trays with temperature decreasing, it cools progressively. Hydrocarbons with lower boiling points condense at higher levels of the tower. This allows the continuous withdrawal of light fractions such as liquefied petroleum gas, naphtha, kerosene, and gas oil.<ref name=":6" />

Since the initial fractions obtained from atmospheric distillation are mostly the result of physical separation, they cannot break the products into smaller molecules. Those distilled heavy molecules are hardly suitable for the commercial market. Thus, refineries rely heavily on cracking processes to convert these high-molecular-weight hydrocarbons into higher-value, lighter liquid fuels. This process involves the thermal or catalytic breaking of carbon-carbon covalent bonds in long-chain alkanes. Modern chemical engineering uses Fluid Catalytic Cracking (FCC) as the primary process. The market prefers this method due to its ability to maximize high-value gasoline yields from heavy gas oils. The efficiency of FCC is highly influenced by the use of highly active, acidic zeolite catalysts. Zeolite selectively accelerates secondary hydrocarbon cracking while minimizing unwanted coke formation. Alternatively, for middle distillates such as jet fuel and diesel, hydrocracking is used. This process takes place in a high-temperature, high-pressure, hydrogen-rich environment. Over catalysts, the hydrogen saturates aromatic rings and breaks the carbon chains.<ref name=":6" />

Reforming is another chemical process that changes a molecule's structure without altering the overall number of carbon atoms. This method is mainly used for straight-run naphtha, a distillation product. Straight-run naphtha has a suitable molecular size for vehicle engines, but the straight-chain alkanes it contains can cause knocking. Reforming uses chemical reactions to trigger isomerization, cyclization or dehydration of the straight chains. During catalytic reforming, a large amount of hydrogen is formed as a byproduct of dehydrogenation. This is great in the engineering industry, since hydrogen can be pumped straight to hydrotreating. Hydrotreating is a process for purifying. Crude oil naturally contains heteroatom impurities like sulfur, nitrogen, and heavy metals. With the purification process, SOx and NOx won't be released during burning, thereby preventing catalyst poisoning. Under high pressure and temperature, hydrogen can convert sulfur and nitrogen into H2S and NH3, separating the impurities completely.<ref name=":6" />

Through the physical separations and chemical alterations described above, crude oil ultimately becomes market products and plays an important role in the global economy. These outputs are broadly divided into three categories: transportation fuels, industrial specialty products, and petrochemical feedstocks. Transportation fuels such as gasoline, diesel, and kerosene sustain global logistics and transportation networks daily. They determine whether the international trade markets can function efficiently. Industrial specialty products like asphalt, which is extracted from heavy residues, play an indispensable role as the structural binder in global infrastructure development. Nevertheless, straight-run naphtha that serves as a petrochemical feedstock has been a source for the global chemical industry. Through steam cracking, primary light olefins and aromatics are synthesized. Thus, downstream polymerization can convert them into ubiquitous materials such as polyethylene, polypropylene, and synthetic rubbers.<ref>Levi, P. G., & Cullen, J. M. (2018). Mapping Global Flows of Chemicals: From Fossil Fuel Feedstocks to Chemical Products. ''Environmental science & technology'', ''52''(4), 1725–1734. <nowiki>https://doi.org/10.1021/acs.est.7b04573</nowiki></ref>

== Environmental issues ==
When it comes to gas and oil extraction, environmental concerns are always on the table. Is the project sustainable? Will the extraction cause any irreparable damage to the Earth's environment? Are the operations negatively affecting other living beings' natural habitats? These are all the questions that geologists and engineers constantly ask themselves. To comprehensively assess environmental issues, both onshore and offshore oil and gas developments must be considered.

Onshore operations are raising the risks of induced earthquakes. Engineering techniques used in unconventional reservoirs, such as hydraulic fracturing and wastewater injection, alter subsurface pore-fluid pressure and reduce the shear strength of the original faults. This may increase the possibility of fault slippage, thus triggering seismic events. This phenomenon is particularly frequent in areas with active shale gas extraction. A case study in the Western Canada Sedimentary Basin (WCSB) in northeastern British Columbia, Canada, shows that the high-density hydraulic fracturing and fluid reinjection activities have led to a significant increase in regional background seismicity in recent years. To manage and minimize the damage caused by this issue, both geological and engineering knowledge are required. Since the fault slippage cannot be observed on the surface, a high-precision underground detector must be introduced. The seismic technology used for exploration can now serve as microseismic monitoring networks. Their ability to map subsurface fracture propagation in real time helps detect microseismic events and acoustic emissions. Collaborating with the Traffic Light Protocols (TLPs), which set the seismic magnitude thresholds, operations will be controlled automatically. Once the magnitude reaches a certain level, restrictions such as limiting injection rates or even mandatory shut-in will be imposed immediately.<ref>Pozzobon, C., Liu, Y., Kirkpatrick, J. D., Chesnaux, R., & Kang, M. (2023). Methane emissions from non-producing oil and gas wells and the potential role of seismic activity: A case study in Northeast British Columbia, Canada. Environmental Science & Technology, 57(51), 21673–21680. <nowiki>https://doi.org/10.1021/acs.est.3c06062</nowiki></ref>

The offshore deep-water oil and gas industry faces distinct issues that experts need to address. Exploration seismic technology relies on high-energy acoustic pulses. The noises can travel very far underwater and disrupt the behavioural patterns of some marine mammals that depend heavily on echolocation. The disruption might cause them to show abnormal behaviour, suffer hearing loss, or even get stranded. Spatial and temporal measures must be applied to prevent serious damage to these animals. Governments should establish avoidance rules and marine protected areas to regulate interactions between the extraction team and marine life. Restricted windows must be strictly obeyed during migration and breeding seasons. Minimum buffer zones should be built around sensitive ecological communities to isolate direct physical and acoustic impact.<ref>Cordes, E. E., Jones, D. O. B., Schlacher, T. A., Amon, D. J., Bernardino, A. F., Brooke, S., Carney, R., DeLeo, D. M., et al. (2016). Environmental impacts of the deep-water oil and gas industry: A review to guide management strategies. ''Frontiers in Environmental Science, 4'', Article 58. <nowiki>https://doi.org/10.3389/fenvs.2016.00058</nowiki></ref> Furthermore, the produced water extracted with crude oil is highly toxic and will cause serious environmental consequences if discharged directly into the ocean. It contains a high concentration of salt, toxic dissolved heavy metals and polycyclic aromatic hydrocarbons. Bioaccumulation and chronic toxicity can negatively affect every step of the marine food chain and damage ecosystems. Multi-step purification must be applied using engineering methods such as physical sedimentation, membrane separation, and advanced oxidation. Systematic inspection will ensure compliance with the standards for discharge or reinjection.<ref>Fakhru’l‑Razi, A., Pendashteh, A., Abdullah, L. C., Biak, D. R. A., Madaeni, S. S., & Abidin, Z. Z. (2009). Produced water treatment and reuse: A review. Journal of Hazardous Materials, 170(2–3), 530–551. <nowiki>https://doi.org/10.1016/j.jhazmat.2009.05.044</nowiki></ref>

== Connections to Our Majors ==
[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]Our group chose the topic of the oil and gas industry because it provides a strong connection between geology, chemistry, and engineering. We were interested in understanding how geological processes create the natural resources that are transformed into usable industrial products. Geology explains how hydrocarbons are generated, migrated, and trapped within the subsurface. Chemistry helps us to understand the fundamental compositions of the crude materials in their carbon and hydrogen form. Chemistry also helps when synthesizing usable products from petroleum. Engineering applies this knowledge to the exploration, extraction, processing, and distribution of these resources.

Some of our group members have direct experience in these types of natural gas engineering. One group member completed a year of co-op with an oil and gas company doing work including reservoir optimization, geological modeling, and seismic data analysis. Another group member is a current intern doing battery engineering research focused on developing cleaner and more effective alternatives, which closely related with the importance of energy storage technology. We all want a positive transition into a more sustainable energy future. With this project, we have the opportunity to connect what we learn in our courses to applicable modern technologies and ways of living.

== Conclusion ==
In conclusion, oil and gas are important resources that connect geology to modern engineering and the environment. The formation of oil and natural gas involves how hydrocarbons form underground, the elements necessary to do so, and the traits that make a reservoir economically viable. Their exploration and production rely on modern technologies, including seismic survey and simulation modelling, and chemical engineering is embedded into this system to turn crude oil into products. The conversion is a detailed chemical process, and onshore and offshore environmental issues are assessed and monitored by new technologies used by geologists and engineers. These connections demonstrate geological resources that are used as energy and materials to support modern society, and also emphasize the importance of responsible resource development.

== Group Contributions and AI Statement ==

=== Breakdown of group contributions: ===
Marijke:

* Introduction to Petroleum Systems
* Geological Formation
* Reservoir Quality

Yuzhou:

* Oil and Gas Exploration: Seismic Technology
* Oil and Gas Extraction: How Geology Determines Engineering Decisions
Keming:
* Chemical Engineering and Petroleum Products
* Environmental Issues

=== AI Statement: ===
AI tools were used to support brainstorming ideas and to delegate portions within the group. AI-generated images are used and cited. Some grammatical checks were made with AI. All final written content have been created and reviewed by all group members.

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-18T02:25:12Z

KemingWu: /* Introduction to Petroleum Systems */

==Introduction to Petroleum Systems==

Oil and natural gas are among the most important geological resources utilized by modern society. This industry fuels the global economy and energy is used for electricity, transportation, and industrial manufacturing. The oil and gas industry is considered in three main sectors<ref name=":3">{{Cite web|last=McClay|first=R.|date=2025-10-12|title=Understanding the Oil and Gas Industry: A Comprehensive Overview|url=https://www.investopedia.com/investing/oil-gas-industry-overview/|url-status=live|website=Investopedia}}</ref>:
{| class="wikitable"
|'''Upstream Sector'''
|'''Midstream Sector'''
|'''Downstream Sector'''
|-
|Include exploration and production. Companies drill for oil and gas.
|Include transportation and usage. Companies handle transit to oil refineries.
|Include refining and distribution. Companies produce refined oil and gas and sell it as gasoline and jet fuel.
|}
Oil and gas consists of hydrocarbons that form naturally within Earth’s crust over millions of years. Organic material derived from plants, animals, and microbes accumulate within depositions, and over geological time, become incorporated into sedimentary rocks. These rocks include sandstone, limestone, and shale, and form in ancient oceans. Burial beneath additional sediment subjects organic matter to high temperatures and pressures, leading to the formation of oil and natural gas within the subsurface<ref name=":3" />.

Hydrocarbons may migrate through porous and permeable sedimentary rocks, as they are less dense than surrounding water. An oil and gas reservoir is created when migrating hydrocarbons reach a barrier. These are the types of reservoirs that are used by the petroleum industry, obtained by drilling through overlying rocks into the subsurface<ref name=":3" />.

The geological formation of oil and gas, including the essential elements and processes, describe the way that hydrocarbons accumulate within the Earth's subsurface. In order for a reservoir to be viable, it must also demonstrate certain qualities, including porosity and permeability, that support hydrocarbon storage.

The oil exploration and extraction part show how geology contribute to the modern reservoir detection and production stage. A few technologies like seismic survey and reservoir simulation also been introduced to show the importance of geological information to engineering decisions.

The petroleum industry is closely related to chemistry and engineering. Geology identifies the source rocks, reservoirs, seals, and migration pathways required for hydrocarbon accumulation. Chemistry helps to explain the transformation into petroleum under changing pressure and temperatures. This influences engineering decisions related to exploration, production, and resource development. Petroleum systems demonstrate how geological processes create conditions for both chemical and engineering applications.

The environmental issues from the oil and gas industry, including onshore induced seismicity and offshore ecological threats, have to be assessed seriously. To control these impacts, geologists and engineers take responsibility for introducing seismic monitoring techniques and protective restrictions.

== Geological Formation ==
The occurrence of oil and gas within the Earth’s crust is demonstrated by a geological framework known as the Total Petroleum System<ref name=":4">{{Cite journal|last=Magoon|first=L. B.|last2=Schmoker|first2=J. W.|date=2000|title=The Total Petroleum System - The Natural Fluid Network that Constrains the Assessment Unit|url=https://pubs.usgs.gov/dds/dds-060/chaps/PS.pdf|journal=United States Geological Survey|pages=1-20}}</ref>. This is the basis for assessing hydrocarbon resources, as it considers both geological elements and processes required for the accumulations to exist. A petroleum system consists of four essential geological elements; source rock, reservoir rock, seal rock, and overburden rock. Together with these elements, the essential processes of the Total Petroleum System are generation, migration, accumulation, and trap formation. The first stage of oil and gas formation is hydrocarbon generation within a source rock, defined as the origin of petroleum within the system. The “pod of active source rock” are adjacent source rocks that are responsible for generating hydrocarbons. Under high temperature and pressure conditions, hydrocarbons are expelled from the source rock and into surrounding rocks<ref name=":4" />.

Once generated, hydrocarbons migrate through the subsurface. A petroleum system requires pathways that allow the oil and gas to move from the source rock and into geological formations that can store hydrocarbons. Without migration pathways, generated hydrocarbons would remain trapped within the source rock and accumulations would not form<ref name=":4" />.
[[File:Figure 1. Geological Cross-Section of an OIl and Gas Reservoir.png|thumb|514x514px|Figure 1. Geological Cross-Section of an Oil and Gas Reservoir]]
Hydrocarbons accumulate within the pores of reservoir rocks. Reservoir rocks are essential to the petroleum system since they provide space for hydrocarbon storage. Reservoir characterization studies evaluate properties including porosity and permeability; qualities that dictate the amount of available hydrocarbon storage as well as the ease that fluid can move within the rock. Reservoir rocks with high porosity and permeability are considered more effective at storing hydrocarbons<ref name=":5" />.

For hydrocarbons to remain within a reservoir, a seal rock must also be present. Seal rocks are identified as one of the four essential petroleum system elements because they act as barriers that restrict fluid movement and prevent hydrocarbons from escaping. Additionally, trap formation must occur to retain migrating hydrocarbons. The process of accumulation and trap formation are together required to create and preserve petroleum deposits<ref name=":4" />.

The final essential element of a petroleum system is overburden rock. Overburden refers to the layers of sediment and rock that accumulate above the source rock and reservoir rock over geological time. As additional sediments are deposited, the increasing thickness of overburden subjects underlying rocks to higher temperatures and processes during burial. These conditions influence the thermal maturity of source rocks and play a crucial role in hydrocarbon generation. Therefore, the thickness and burial history over the overburden can be used by geologists to determine whether or not the source rocks have reached the temperature and pressure conditions that are necessary for oil and gas formation<ref name=":4" />.

== Reservoir Quality ==

The presence of a petroleum system alone does not always guarantee that hydrocarbons can be recovered economically. Reservoir quality is primarily determined by porosity and permeability, which are considered the fundamental factors of the petroleum reservoir viability. Porosity refers to the amount of pore space available within a rock for hydrocarbon storage, while permeability describes the degree to which fluids can move through connected pore networks. Reservoir rocks may contain significant pore space but still be considered poor-quality if pore connections are limited. Consequently, both properties must be evaluated when assessing whether or not a reservoir is considered commercially viable. Other important factors of reservoir quality include depositional environment, sediment provenance, weathering, compaction, dissolution, burial depth, pressure, and structural deformation. Since these controls interact over millions of years, reservoir quality reflects cumulative effects, from the time of sediment deposition<ref name=":5" />.

One of the most important controls on reservoir quality is the depositional environment in which the sediment was originally deposited. The primary composition of sediment strongly influences the future evolution of reservoir rocks. In sandstone reservoirs, factors such as the source-area geology, climate, topography, and grain size all affect the resulting rock properties. These factors all influence pore space, and therefore impact reservoir quality. Sediments deposited in shallow marine environments often develop better reservoir properties because they tend to be cleaner and contain fewer fine materials that can reduce pore connections. On the other hand, sediments deposited in low-energy environments may contain more clay and silt, which can negatively affect reservoir quality. Well-sorted sediments generally have more interconnected pores than poorly sorted sediments that contain fine grain matrix material<ref name=":5" />.

Different lithologies also respond differently to geological processes. Sandstone reservoirs are among the most common hydrocarbon reservoirs because they can preserve great porosity between sediment grains. Carbonate reservoirs, including limestone and dolostone, often undergo many diagenetic changes through processes such as dissolution, recrystallization, and dolomitization due to their greater chemical reactivity. Rather than relying solely on primary pore space, carbonate reservoirs often develop secondary porosity through diagenesis and fracturing. As a result, both sandstone and carbonate reservoirs often have the capacity to contain hydrocarbons, although having very different pore systems and geological histories<ref name=":5" />.

Following deposition, sediment undergoes diagenesis when physical and chemical changes occur as the sediment is transformed into sedimentary rock. Important stages in reservoir evolution include eodiagenesis (early burial diagenesis), mesodiagenesis (burial diagenesis), and telodiagenesis (uplift-related changes)<ref name=":5" />. During these stages, sediments experience compaction, dissolution, mineral replacement, fracturing, and fluid interactions that can significantly alter reservoir properties. These diagenetic processes can reduce reservoir quality. Compaction during burial decreases pore space as sediment gains become more tightly packed. Chemical compaction and pressure solution may further reduce porosity. Minerals such as quartz, calcite, dolomite, and clay can fill pore spaces and restrict fluid movement. Quartz cementation is identified as one of the most important pore-filling processes in deep buried sandstone reservoirs because of the way it reduces the amount of available pore space progressively. Clay mineral does so similarly and may significantly decrease permeability by blocking pores and restricting fluid flow <ref name=":5">{{Cite journal|last=Worden|first=R. H.|last2=Armitage|first2=P. J.|last3=Butcher|first3=A. R.|last4=Churchill|first4=J. M.|last5=Csoma|first5=A. E.|last6=Hollis|first6=C.|last7=Lander|first7=R. H.|last8=Omma|first8=J. E.|date=2018|title=Petroleum reservoir quality prediction: overview and contrasting approaches from sandstone and carbonate communities|url=https://doi.org/10.1144/SP435.21|journal=Geological Society|volume=435|pages=1-31}}</ref>.

Reservoir quality is not solely determined by burial and porosity. The final characteristics of a reservoir are reflected by the preservation of the pore space. Reservoirs with similar depositional origination may exhibit very different porosity and permeability depending on their diagenetic history and the geological conditions they experienced during burial and uplift<ref name=":5" />.
== Oil and Gas Exploration: Seismic Technology ==

Now we know the formation of oil and gas, the next question is where to locate them. Since reservoirs are below the surface, geologists cannot directly see where they are before drilling. This makes drilling a gamble, and that's where seismic reflection technology contributes to lowering the risk. It works as a tool that helps geologists to create an image of what is beneath the surface before they decide where to drill <ref name=":0">{{Cite journal|last=Mohammed|first=Farfour|date=2016-05-01|title=A review on multicomponent seismology: A potential seismic application for reservoir characterization|url=https://www.sciencedirect.com/science/article/pii/S2090123215001125|journal=Journal of Advanced Research|volume=3|pages=515-524}}</ref>.[[File:Seismic_Survey_and_Mechanism.png|thumb|left|500x500px|Figure 1. Seismic Technology and Mechanism for oil Exploration]]The working principle behind seismic is to use energy waves to explore underground rock layers. During a survey, energy waves are sent into the ground. When waves hit the boundaries between rock layers, some of the energy bounces back to the surface, while some goes further. Receivers then pick up these reflected waves and give information about the depth, shape and arrangement of subsurface layers by analyzing the different waves using the pre-known typical rock’s density and acoustic impedance. After processing, the data can be shown as profiles or 3D seismic images <ref>{{Cite journal|last=Ilya|first=Tsvankin|date=2010-09-01|title=Seismic anisotropy in exploration and reservoir characterization: An overview|url=https://www.researchgate.net/publication/228633261_Seismic_anisotropy_in_exploration_and_reservoir_characterization_An_overview|journal=Geophysics|volume=75}}</ref>.

This is essential because oil and gas need geological structures to build up, and seismic interpretation helps identify these structures. For example, folds show up as layers in seismic images. If the fold creates an anticline, oil and gas might move upward and get trapped near the top. Faults can be spotted when rock layers are broken or displaced. Faults can create traps but might let hydrocarbons escape if they aren't sealed properly. Therefore, seismic data is not just used to "find oil", it helps us understand if subsurface geology has the right structure to store oil and gas<ref>{{Cite journal|last=Lawson|first=M.|date=2018-02-19|title=Geochemical applications in petroleum systems analysis: New constraints and the power of integration|url=https://www.researchgate.net/publication/323282762_Geochemical_applications_in_petroleum_systems_analysis_New_constraints_and_the_power_of_integration|journal=Geological Society, London, Special Publications|volume=468|pages=6}}</ref> . Beyond locating the reservoir, seismic technology also helps geologists understand the environmental geometry. This includes the shape, thickness, depth and continuity of a reservoir. This matters because a reservoir can be located but not profitable for business. With current technology and the purpose of maximizing the future extraction, geologists are targeting large and continuous reservoirs rather than thin and isolated ones. Seismic data can help pinpoint the drilling target by showing where the reservoir may be thicker or larger<ref name=":0" /> .

An exploration workflow usually starts with a regional study. The first step is for geologists to determine if the region has a petroleum system with possible traps that contain oil. Next, follow-up seismic surveys help to collect evidence and more information. Further, geoscientists interpret the data to distinguish geological structures and possible drilling targets. These decisions are assisted by other data, such as core samples <ref name=":1">{{Cite journal|last=Ma|first=Yuan Zhe|date=2011-01-01|title=Uncertainty Analysis in Reservoir Characterization and Management: How Much Should We Know About What We Don't Know?|url=https://pubs.geoscienceworld.org/aapg/books/edited-volume/1248/chapter-abstract/107059711/Uncertainty-Analysis-in-Reservoir-Characterization?redirectedFrom=fulltext|journal=AAPG Memoir|volume=1|pages=15}}</ref>.

However, seismic technology is not perfect. As an imaging technique that relies on the reflection of waves, some thin reservoirs or structures can be hard to detect. Also, seismic data cannot directly show the oil and gas but uses structures to infer their existence. Based on this limitation, seismic technology is more like a tool that reduces drilling risk than eliminates all uncertainties <ref>Saad, M. R., & Jadeer, A.-S. (2022). ''Seismic Method for Exploration Oil and Gas Reservoirs''. <nowiki>https://doi.org/10.1007/978-981-99-1964-2_89</nowiki></ref>.

== Oil and Gas Extraction: How Geology Determines Engineering Decisions ==
Once an oil reservoir is proven as continuous and profitable, geology still plays a role in deciding how to extract the resources. In practice, engineering decisions and extraction methods are based on how the subsurface is structured and how fluids move through the rock.

Engineers need further geological information before deciding where to drill. They need to know the depth of the potential drilling trajectory, the thickness of the oil reservoir, and the fluid contacts of the reservoir to optimize the performance. For example, a rich oil-bearing zone in the reservoir should be the highest priority to place the well nearby. However, if the zone is disrupted by some faults, then engineers and geologists must determine whether these faults connect to parts of the reservoir or cut it into separate parts. Moreover, if the production well is too close to a water or gas zone, a water or gas breakthrough is likely to happen and reduce oil production. In a real-world case, a breakthrough can easily turn a high-production well into a shut-down.
[[File:Reservori_Simulation_Model.jpg|thumb|Figure 2. The reservoir modeling workflow showing the sequence of stages in data acquisition and interpretation<ref name=":2">Abel, M., Garcia, L., Lorenzatti, A., & De Ros, L. (2010, October 26). ''SEMANTIC INTEROPERABILITY IN THE PETROLEUM CHAIN: THE CONTRIBUTION OF ONTOLOGICAL ANALYSIS''.</ref>|549x549px]]Reservoir simulation is a great tool to use in oil extraction, just like how seismic technology assists oil exploration. A reservoir model is a digital version of a reservoir with a vivid representation of reservoir structures and various relevant properties like pressure, permeability, porosity, and saturation of each phase. Engineers use this model to predict how the reservoir might behave during production. For instance, the model can estimate production rates, pressure changes, and any potential water cut. It can also achieve optimization on certain jobs, like comparing different production plans and well placement strategies. Since the model is built purely based on geological data, its quality varies depending on how well the regional geology is captured and understood, and this can also be a limitation of the reservoir model <ref name=":2" /><ref>Sambo, C., Iferobia, C. C., Babasafari, A. A., Rezaei, S., & Akanni, O. A. (2020). The Role of Time Lapse(4D) Seismic Technology as Reservoir Monitoring and Surveillance Tool: A Comprehensive Review. ''Journal of Natural Gas Science and Engineering'', ''80'', 103312. <nowiki>https://doi.org/10.1016/j.jngse.2020.103312</nowiki></ref>.

Since there are many different types of reservoirs, extraction methods have also been developed differently to achieve efficient production for each case. And they can be separated under two main reservoir types: conventional and unconventional.
{| class="wikitable"
|+
!Reservoir Type
!Geological Characteristics
!Main Extraction Methods
!Engineering
Reason
|-
|Conventional reservoirs
|High permeability and porosity for fluids to flow naturally toward the well through connected pore spaces
|Primary production relies on natural reservoir pressure and secondary recovery methods like water injection are used to maintain the pressure
|Maintain and increase reservoir pressure to improve flow toward production wells
|-
|Unconventional reservoirs
|Low permeability so fluids are trapped in rocks or exist as highly viscous bitumen
|Horizontal drilling and hydraulic fracturing are commonly used for shale gas and tight oil
For deep oil sands, steam-assisted gravity drainage can be used by injecting steam underground to heat bitumen and lower the viscousity
|Create flow pathways to make hydrocarbons mobile enough to be produced
|}
Overall, geology has a strong influence on engineering decisions in oil and gas extraction. Geology informs engineers to know the reservoir quality, what extraction methodology can be applied, and what risks might exist during production. Geological information has also been integrated into reservoir models to provide a more in-depth understanding and optimization. Oil extraction is not just about improving equipment and technology, it is also a process in which geological knowledge is applied with engineering decisions.

== Chemical Engineering and Petroleum Products ==
[[File:Fractional Distillation.jpg|thumb|Fractional Distillation Process of Crude Oil<ref>[https://wigmoretrading.com/what-is-the-fractional-distillation-process-of-oil-in-nigeria/]</ref>|512x512px]]
Crude oil, in its unrefined state, has almost no direct utility due to its highly complex molecular constitution. It exists fundamentally as a dense, complex mixture of hundreds of different hydrocarbons. The three basic components of crude oil are alkanes, cycloalkanes, and aromatics. The primary steps of chemical engineering within petroleum refineries are physical separation and chemical conversion. The first step separates the heterogeneous mixture into narrower, manageable fractions based on physical properties, and the second step upgrades these fractions into high-value, commercially viable products. This transformation from raw, unusable crude oil into high-value fuels relies on a sequence of thermal processes and complex catalytic reactions that manipulate molecular structures.<ref name=":6">Gary, J.H., Handwerk, J.H., Kaiser, M.J., & Geddes, D. (2007). Petroleum Refining: Technology and Economics, Fifth Edition (5th ed.). CRC Press. <nowiki>https://doi.org/10.4324/9780203907924</nowiki></ref>

The foundational stage of any refinery configuration is fractional distillation. The process depends on the differential volatility and boiling points of the constituent hydrocarbons within crude oil. Fractional distillation is commonly operationalized through the Atmospheric Distillation Unit, and crude oil is preheated to approximately 350-400°C, then pumped into the lowest and hottest level in the fractional distillation tower. As the vaporized oil ascends through a series of distillation trays with temperature decreasing, it cools progressively. Hydrocarbons with lower boiling points condense at higher levels of the tower. This allows the continuous withdrawal of light fractions such as liquefied petroleum gas, naphtha, kerosene, and gas oil.<ref name=":6" />

Since the initial fractions obtained from atmospheric distillation are mostly the result of physical separation, they cannot break the products into smaller molecules. Those distilled heavy molecules are hardly suitable for the commercial market. Thus, refineries rely heavily on cracking processes to convert these high-molecular-weight hydrocarbons into higher-value, lighter liquid fuels. This process involves the thermal or catalytic breaking of carbon-carbon covalent bonds in long-chain alkanes. Modern chemical engineering uses Fluid Catalytic Cracking (FCC) as the primary process. The market prefers this method due to its ability to maximize high-value gasoline yields from heavy gas oils. The efficiency of FCC is highly influenced by the use of highly active, acidic zeolite catalysts. Zeolite selectively accelerates secondary hydrocarbon cracking while minimizing unwanted coke formation. Alternatively, for middle distillates such as jet fuel and diesel, hydrocracking is used. This process takes place in a high-temperature, high-pressure, hydrogen-rich environment. Over catalysts, the hydrogen saturates aromatic rings and breaks the carbon chains.<ref name=":6" />

Reforming is another chemical process that changes a molecule's structure without altering the overall number of carbon atoms. This method is mainly used for straight-run naphtha, a distillation product. Straight-run naphtha has a suitable molecular size for vehicle engines, but the straight-chain alkanes it contains can cause knocking. Reforming uses chemical reactions to trigger isomerization, cyclization or dehydration of the straight chains. During catalytic reforming, a large amount of hydrogen is formed as a byproduct of dehydrogenation. This is great in the engineering industry, since hydrogen can be pumped straight to hydrotreating. Hydrotreating is a process for purifying. Crude oil naturally contains heteroatom impurities like sulfur, nitrogen, and heavy metals. With the purification process, SOx and NOx won't be released during burning, thereby preventing catalyst poisoning. Under high pressure and temperature, hydrogen can convert sulfur and nitrogen into H2S and NH3, separating the impurities completely.<ref name=":6" />

Through the physical separations and chemical alterations described above, crude oil ultimately becomes market products and plays an important role in the global economy. These outputs are broadly divided into three categories: transportation fuels, industrial specialty products, and petrochemical feedstocks. Transportation fuels such as gasoline, diesel, and kerosene sustain global logistics and transportation networks daily. They determine whether the international trade markets can function efficiently. Industrial specialty products like asphalt, which is extracted from heavy residues, play an indispensable role as the structural binder in global infrastructure development. Nevertheless, straight-run naphtha that serves as a petrochemical feedstock has been a source for the global chemical industry. Through steam cracking, primary light olefins and aromatics are synthesized. Thus, downstream polymerization can convert them into ubiquitous materials such as polyethylene, polypropylene, and synthetic rubbers.<ref>Levi, P. G., & Cullen, J. M. (2018). Mapping Global Flows of Chemicals: From Fossil Fuel Feedstocks to Chemical Products. ''Environmental science & technology'', ''52''(4), 1725–1734. <nowiki>https://doi.org/10.1021/acs.est.7b04573</nowiki></ref>

== Environmental issues ==
When it comes to gas and oil extraction, environmental concerns are always on the table. Is the project sustainable? Will the extraction cause any irreparable damage to the Earth's environment? Are the operations negatively affecting other living beings' natural habitats? These are all the questions that geologists and engineers constantly ask themselves. To comprehensively assess environmental issues, both onshore and offshore oil and gas developments must be considered.

Onshore operations are raising the risks of induced earthquakes. Engineering techniques used in unconventional reservoirs, such as hydraulic fracturing and wastewater injection, alter subsurface pore-fluid pressure and reduce the shear strength of the original faults. This may increase the possibility of fault slippage, thus triggering seismic events. This phenomenon is particularly frequent in areas with active shale gas extraction. A case study in the Western Canada Sedimentary Basin (WCSB) in northeastern British Columbia, Canada, shows that the high-density hydraulic fracturing and fluid reinjection activities have led to a significant increase in regional background seismicity in recent years. To manage and minimize the damage caused by this issue, both geological and engineering knowledge are required. Since the fault slippage cannot be observed on the surface, a high-precision underground detector must be introduced. The seismic technology used for exploration can now serve as microseismic monitoring networks. Their ability to map subsurface fracture propagation in real time helps detect microseismic events and acoustic emissions. Collaborating with the Traffic Light Protocols (TLPs), which set the seismic magnitude thresholds, operations will be controlled automatically. Once the magnitude reaches a certain level, restrictions such as limiting injection rates or even mandatory shut-in will be imposed immediately.<ref>Pozzobon, C., Liu, Y., Kirkpatrick, J. D., Chesnaux, R., & Kang, M. (2023). Methane emissions from non-producing oil and gas wells and the potential role of seismic activity: A case study in Northeast British Columbia, Canada. Environmental Science & Technology, 57(51), 21673–21680. <nowiki>https://doi.org/10.1021/acs.est.3c06062</nowiki></ref>

The offshore deep-water oil and gas industry faces distinct issues that experts need to address. Exploration seismic technology relies on high-energy acoustic pulses. The noises can travel very far underwater and disrupt the behavioural patterns of some marine mammals that depend heavily on echolocation. The disruption might cause them to show abnormal behaviour, suffer hearing loss, or even get stranded. Spatial and temporal measures must be applied to prevent serious damage to these animals. Governments should establish avoidance rules and marine protected areas to regulate interactions between the extraction team and marine life. Restricted windows must be strictly obeyed during migration and breeding seasons. Minimum buffer zones should be built around sensitive ecological communities to isolate direct physical and acoustic impact.<ref>Cordes, E. E., Jones, D. O. B., Schlacher, T. A., Amon, D. J., Bernardino, A. F., Brooke, S., Carney, R., DeLeo, D. M., et al. (2016). Environmental impacts of the deep-water oil and gas industry: A review to guide management strategies. ''Frontiers in Environmental Science, 4'', Article 58. <nowiki>https://doi.org/10.3389/fenvs.2016.00058</nowiki></ref> Furthermore, the produced water extracted with crude oil is highly toxic and will cause serious environmental consequences if discharged directly into the ocean. It contains a high concentration of salt, toxic dissolved heavy metals and polycyclic aromatic hydrocarbons. Bioaccumulation and chronic toxicity can negatively affect every step of the marine food chain and damage ecosystems. Multi-step purification must be applied using engineering methods such as physical sedimentation, membrane separation, and advanced oxidation. Systematic inspection will ensure compliance with the standards for discharge or reinjection.<ref>Fakhru’l‑Razi, A., Pendashteh, A., Abdullah, L. C., Biak, D. R. A., Madaeni, S. S., & Abidin, Z. Z. (2009). Produced water treatment and reuse: A review. Journal of Hazardous Materials, 170(2–3), 530–551. <nowiki>https://doi.org/10.1016/j.jhazmat.2009.05.044</nowiki></ref>

== Connections to Our Majors ==
[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

== Conclusion ==

== Group Contributions and AI Statement ==

=== Breakdown of group contributions: ===
Marijke:

* Introduction to Petroleum Systems
* Geological Formation
* Reservoir Quality

Yuzhou:

* Oil and Gas Exploration: Seismic Technology
* Oil and Gas Extraction: How Geology Determines Engineering Decisions
Keming:
* Chemical Engineering and Petroleum Products
* Environmental Issues

=== AI Statement: ===
AI tools were used to support brainstorming ideas and to delegate portions within the group. AI-generated images are used and cited. Some grammatical checks were made with AI. All final written content have been created and reviewed by all group members.

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-18T01:28:46Z

KemingWu:

== Summary ==

== Statement of connection and why you chose it ==
The connections between your major and geology, including reasons you chose this particular connection, are clearly articulated

==Introduction to Petroleum Systems==

Oil and natural gas are among the most important geological resources utilized by modern society. This industry fuels the global economy and energy is used for electricity, transportation, and industrial manufacturing. The oil and gas industry is considered in three main sectors<ref name=":3">{{Cite web|last=McClay|first=R.|date=2025-10-12|title=Understanding the Oil and Gas Industry: A Comprehensive Overview|url=https://www.investopedia.com/investing/oil-gas-industry-overview/|url-status=live|website=Investopedia}}</ref>:
{| class="wikitable"
|'''Upstream Sector'''
|'''Midstream Sector'''
|'''Downstream Sector'''
|-
|Include exploration and production. Companies drill for oil and gas.
|Include transportation and usage. Companies handle transit to oil refineries.
|Include refining and distribution. Companies produce refined oil and gas and sell it as gasoline and jet fuel.
|}
Oil and gas consists of hydrocarbons that form naturally within Earth’s crust over millions of years. Organic material derived from plants, animals, and microbes accumulate within depositions, and over geological time, becomes incorporated into sedimentary rocks. These rocks include sandstone, limestone, and shale, and form in ancient oceans. Burial beneath additional sediment subjects organic matter to high temperatures and pressures, leading to the formation of oil and natural gas within the subsurface<ref name=":3" />.

Hydrocarbons may migrate through porous and permeable sedimentary rocks, as they are less dense than surrounding water. An oil and gas reservoir is created when migrating hydrocarbons reach a barrier. These are the types of reservoirs that are used by the petroleum industry by drilling through overlying rocks into the subsurface reservoir<ref name=":3" />.

The petroleum industry is closely related to chemistry and engineering. Geology identifies the source rocks, reservoirs, seals, and migration pathways required for hydrocarbon accumulation, while chemistry helps explain the transformation into petroleum under changing pressure and temperatures. This directly influences engineering decisions related to exploration, production, and resource development. Petroleum systems demonstrate how geological processes create conditions for both chemical and engineering applications.

== Geological Formation ==
The occurrence of oil and gas within the Earth’s crust is demonstrated by a geological framework known as the Total Petroleum System<ref name=":4">{{Cite journal|last=Magoon|first=L. B.|last2=Schmoker|first2=J. W.|date=2000|title=The Total Petroleum System - The Natural Fluid Network that Constrains the Assessment Unit|url=https://pubs.usgs.gov/dds/dds-060/chaps/PS.pdf|journal=United States Geological Survey|pages=1-20}}</ref>. This is the basis for assessing hydrocarbon resources, as it considers both geological elements and processes required for the accumulations to exist. A petroleum system consists of four essential geological elements; source rock, reservoir rock, seal rock, and overburden rock. The essential processes of the Total Petroleum System are generation, migration, accumulation, and trap formation. The first stage of oil and gas formation is hydrocarbon generation within a source rock, defined as the origin of petroleum within the system. The “pod of active source rock” are adjacent source rocks that are responsible for generating hydrocarbons. Under high temperature and pressure conditions, hydrocarbons are expelled from the source rock and into surrounding rock units<ref name=":4" />.

Once generated, hydrocarbons migrate through the subsurface. A petroleum system requires pathways that allow the oil and gas to move from the source rock and into geological formations that can store hydrocarbons. Without migration pathways, generated hydrocarbons would remain trapped within the source rock and accumulations would not form<ref name=":4" />.
[[File:Figure 1. Geological Cross-Section of an OIl and Gas Reservoir.png|thumb|514x514px|Figure 1. Geological Cross-Section of an Oil and Gas Reservoir]]
Hydrocarbons accumulate within the pores of reservoir rocks. Reservoir rocks are essential to the petroleum system since they provide space for hydrocarbon storage. Reservoir characterization studies evaluate properties including porosity and permeability; qualities that dictate the amount of available hydrocarbon storage as well as the ease that fluid can move within the rock. Reservoir rocks with high porosity and permeability are considered more effective at storing hydrocarbons<ref name=":5" />.

For hydrocarbons to remain within a reservoir, a seal rock must also be present. Seal rocks are identified as one of the four essential petroleum system elements because they act as barriers that restrict fluid movement and prevent hydrocarbons from escaping. Additionally, trap formation must occur to retain migrating hydrocarbons. The process of accumulation and trap formation are together required to create and preserve petroleum deposits<ref name=":4" />.

The final essential element of a petroleum system is overburden rock. Overburden refers to the layers of sediment and rock that accumulate above the source rock and reservoir rock over geological time. As additional sediments are deposited, the increasing thickness of overburden subjects underlying rocks to higher temperatures and processes during burial. These conditions influence the thermal maturity of source rocks and play a crucial role in hydrocarbon generation. Therefore, the thickness and burial history over the overburden can be used by geologists to determine whether or not the source rocks have reached the temperature and pressure conditions that are necessary for oil and gas formation<ref name=":4" />.

== Reservoir Quality ==

The presence of a petroleum system alone does not guarantee that hydrocarbons can be recovered economically. Reservoir quality is primarily determined by porosity and permeability, which are considered the fundamental factors of the petroleum reservoir viability. Porosity is the amount of pore space available within a rock for hydrocarbon storage, while permeability describes the degree to which fluids can move through connected pore networks. Reservoir rocks may contain significant pore space but still be considered poor-quality if pore connections are limited. Consequently, both properties must be evaluated when assessing whether or not a reservoir is considered commercially viable. Other important factors of reservoir quality include depositional environment, sediment provenance, weathering, compaction, dissolution, burial depth, pressure, and structural deformation. Since these controls interact over millions of years, reservoir quality reflects cumulative effects, looking back to initial sediment<ref name=":5" />.

One of the most important controls on reservoir quality is the depositional environment in which the sediment was originally deposited. The primary composition of sediment strongly influences the future evolution of reservoir rocks. In sandstone reservoirs, factors such as the source-area geology, climate, topography, and grain size all affect the resulting rock properties. These factors all influence pore space, and therefore impact reservoir quality. Sediments deposited in shallow marine environments often develop better reservoir properties because they tend to be cleaner and contain fewer fine materials that can reduce pore connections. On the other hand, sediments deposited in low-energy environments may contain more clay and silt, which can negatively affect reservoir quality. Well-sorted sediments generally have more interconnected pores than poorly sorted sediments that contain fine grain matrix material<ref name=":5" />.

Different lithologies also respond differently to geological processes. Sandstone reservoirs are among the most common hydrocarbon reservoirs because they can preserve great porosity between sediment grains. Carbonate reservoirs, including limestone and dolostone, often undergo many diagenetic changes through processes such as dissolution, recrystallization, and dolomitization due to their greater chemical reactivity. Rather than relying solely on primary pore space, carbonate reservoirs often develop secondary porosity through diagenesis and fracturing. As a result, both sandstone and carbonate reservoirs often have the capacity to contain hydrocarbons, although having very different pore systems and geological histories<ref name=":5" />.

Following deposition, sediment undergoes diagenesis when physical and chemical changes occur as the sediment is transformed into sedimentary rock. Important stages in reservoir evolution include eodiagenesis (early burial diagenesis), mesodiagenesis (burial diagenesis), and telodiagenesis (uplift-related changes)<ref name=":5" />. During these stages, sediments experience compaction, dissolution, mineral replacement, fracturing, and fluid interactions that can significantly alter reservoir properties. These diagenetic processes can reduce reservoir quality. Compaction during burial decreases pore space as sediment gains become more tightly packed. Chemical compaction and pressure solution may further reduce porosity. Minerals such as quartz, calcite, dolomite, and clay can fill pore spaces and restrict fluid movement. Quartz cementation is identified as one of the most important pore-filling processes in deep buried sandstone reservoirs because of the way it reduces the amount of available pore space progressively. Clay mineral does so similarly and may significantly decrease permeability by blocking pores and restricting fluid flow <ref name=":5">{{Cite journal|last=Worden|first=R. H.|last2=Armitage|first2=P. J.|last3=Butcher|first3=A. R.|last4=Churchill|first4=J. M.|last5=Csoma|first5=A. E.|last6=Hollis|first6=C.|last7=Lander|first7=R. H.|last8=Omma|first8=J. E.|date=2018|title=Petroleum reservoir quality prediction: overview and contrasting approaches from sandstone and carbonate communities|url=https://doi.org/10.1144/SP435.21|journal=Geological Society|volume=435|pages=1-31}}</ref>.

Reservoir quality is not solely determined by burial and porosity. The final characteristics of a reservoir are reflected by the preservation of pore space. Reservoirs with similar depositional origination may exhibit very different porosity and permeability depending on their diagenetic history and the geological conditions they experienced during burial and uplift<ref name=":5" />.
== Oil and Gas Exploration: Seismic Technology ==

Now we know the importance of oil and gas to our society, and how they were formed, the next question is where to locate them. Since reservoirs are below the surface, geologists cannot directly see where they are before drilling. This makes drilling a gamble, and that's where seismic reflection technology contributes to lowering the risk. It works as a tool that helps geologists to create an image of what is beneath the surface before they decide where to drill <ref name=":0">{{Cite journal|last=Mohammed|first=Farfour|date=2016-05-01|title=A review on multicomponent seismology: A potential seismic application for reservoir characterization|url=https://www.sciencedirect.com/science/article/pii/S2090123215001125|journal=Journal of Advanced Research|volume=3|pages=515-524}}</ref>.[[File:Seismic_Survey_and_Mechanism.png|thumb|left|500x500px|Figure 1. Seismic Technology and Mechanism for oil Exploration]]The working principle behind seismic is to use energy waves to explore underground rock layers. During a survey, energy waves are sent into the ground. When waves hit the boundaries between rock layers, some of the energy bounces back to the surface, while some goes further. Receivers then pick up these reflected waves and give information about the depth, shape and arrangement of subsurface layers by analyzing the different waves using the pre-known typical rock’s density and acoustic impedance. After processing, the data can be shown as profiles or 3D seismic images <ref>{{Cite journal|last=Ilya|first=Tsvankin|date=2010-09-01|title=Seismic anisotropy in exploration and reservoir characterization: An overview|url=https://www.researchgate.net/publication/228633261_Seismic_anisotropy_in_exploration_and_reservoir_characterization_An_overview|journal=Geophysics|volume=75}}</ref>.

This is essential because oil and gas need geological structures to build up, and seismic interpretation helps identify these structures. For example, folds show up as layers in seismic images. If the fold creates an anticline, oil and gas might move upward and get trapped near the top. Faults can be spotted when rock layers are broken or displaced. Faults can create traps but might let hydrocarbons escape as well if they aren't sealed properly. So seismic data are not just used to "find oil", they help us understand if subsurface geology has the right structure to store oil and gas<ref>{{Cite journal|last=Lawson|first=M.|date=2018-02-19|title=Geochemical applications in petroleum systems analysis: New constraints and the power of integration|url=https://www.researchgate.net/publication/323282762_Geochemical_applications_in_petroleum_systems_analysis_New_constraints_and_the_power_of_integration|journal=Geological Society, London, Special Publications|volume=468|pages=6}}</ref> . More than locating the reservoir, seismic technology also helps geologists understand its geometry. This includes the shape, thickness, depth and continuity of a reservoir. This matters because a reservoir can be located but not profitable for business. With current technology and the purpose of maximizing the future extraction, geologists are targeting large and continuous reservoirs rather than thin and isolated ones. Seismic data can help pinpoint the drilling target by showing where the reservoir might be thicker or larger<ref name=":0" /> .

An exploration workflow usually starts with a regional study. The first step is for geologists to determine if the region has a petroleum system with possible traps that contain oil. Then there are follow-up seismic surveys to get evidence and more information. Next, geoscientists interpret the data to distinguish geological structures and possible drilling targets. These decisions are assisted by other data, such as core samples. Finally, drilling locations are chosen based on different criteria <ref name=":1">{{Cite journal|last=Ma|first=Yuan Zhe|date=2011-01-01|title=Uncertainty Analysis in Reservoir Characterization and Management: How Much Should We Know About What We Don't Know?|url=https://pubs.geoscienceworld.org/aapg/books/edited-volume/1248/chapter-abstract/107059711/Uncertainty-Analysis-in-Reservoir-Characterization?redirectedFrom=fulltext|journal=AAPG Memoir|volume=1|pages=15}}</ref>.

However, seismic technology is not perfect. As an imaging technique that relies on the reflection of waves, some thin reservoirs or structures can be hard to detect. Also, seismic data cannot directly show the oil and gas but uses structures to infer their existence. Based on this limitation, seismic technology is more like a tool that reduces drilling risk than eliminates all uncertainties <ref>Saad, M. R., & Jadeer, A.-S. (2022). ''Seismic Method for Exploration Oil and Gas Reservoirs''. <nowiki>https://doi.org/10.1007/978-981-99-1964-2_89</nowiki></ref>.

== Oil and Gas Extraction: How Geology Determines Engineering Decisions ==
Once an oil reservoir is proven as continuous and profitable, geology still plays a role in deciding how to extract the resources. In a word, engineering decisions and extraction methods are based on how the subsurface looks and how fluids move through the rock.

Engineers need more geology information before deciding where to drill. They want to know the depth of the potential drilling trajectory, the thickness of the oil reservoir, and the fluid contacts of the reservoir to optimize the performance. For example, a rich oil-bearing zone in the reservoir should be the highest priority to place the well nearby. However, if the zone is disrupted by some faults, then engineers and geologists must determine whether these faults connect to parts of the reservoir or cut it into separate parts. Moreover, if the production well is too close to a water or gas zone, a water or gas breakthrough is likely to happen and reduce oil production. In a real-world case, a breakthrough can easily turn a high-production well into a shut-down.
[[File:Reservori_Simulation_Model.jpg|thumb|Figure 2. The reservoir modeling workflow showing the sequence of stages in data acquisition and interpretation<ref name=":2">Abel, M., Garcia, L., Lorenzatti, A., & De Ros, L. (2010, October 26). ''SEMANTIC INTEROPERABILITY IN THE PETROLEUM CHAIN: THE CONTRIBUTION OF ONTOLOGICAL ANALYSIS''.</ref>|549x549px]]Reservoir simulation is a great tool to use in oil extraction, just like how seismic technology assists oil exploration. A reservoir model is a digital version of a reservoir with a vivid representation of reservoir structures and various relevant properties like pressure, permeability, porosity, and saturation of each phase. Engineers use this model to predict how the reservoir might behave during production. For instance, the model can estimate production rates, pressure changes, and any potential water cut. It can also achieve optimization on certain jobs, like comparing different production plans and well placement strategies. Since the model is built purely based on geological data, its quality varies depending on how well the regional geology is captured and understood, and this can also be a limitation of the reservoir model <ref name=":2" /><ref>Sambo, C., Iferobia, C. C., Babasafari, A. A., Rezaei, S., & Akanni, O. A. (2020). The Role of Time Lapse(4D) Seismic Technology as Reservoir Monitoring and Surveillance Tool: A Comprehensive Review. ''Journal of Natural Gas Science and Engineering'', ''80'', 103312. <nowiki>https://doi.org/10.1016/j.jngse.2020.103312</nowiki></ref>.

Since there are many different types of reservoirs, extraction methods have also been developed differently to achieve efficient production for each case. And they can be separated under two main reservoir types: conventional and unconventional.
{| class="wikitable"
|+
!Reservoir Type
!Geological Characteristics
!Main Extraction Methods
!Engineering
Reason
|-
|Conventional reservoirs
|High permeability and porosity for fluids to flow naturally toward the well through connected pore spaces
|Primary production relies on natural reservoir pressure and secondary recovery methods like water injection are used to maintain the pressure
|Maintain and increase reservoir pressure to improve flow toward production wells
|-
|Unconventional reservoirs
|Low permeability so fluids are trapped in rocks or exist as highly viscous bitumen
|Horizontal drilling and hydraulic fracturing are commonly used for shale gas and tight oil
For deep oil sands, steam-assisted gravity drainage can be used by injecting steam underground to heat bitumen and lower the viscousity
|Create flow pathways to make hydrocarbons mobile enough to be produced
|}
Overall, geology has a strong influence on engineering decisions in oil and gas extraction. Geology informs engineers to know the reservoir quality, what extraction methodology can be applied, and what risks might exist during production. Geological information has also been integrated into reservoir models to provide a more in-depth understanding and optimization. Oil extraction is not just about improving equipment and technology, it is also a process in which geological knowledge is applied with engineering decisions.

== Chemical Engineering and Petroleum Products ==
[[File:Fractional Distillation.jpg|thumb|Fractional Distillation Process of Crude Oil<ref>[https://wigmoretrading.com/what-is-the-fractional-distillation-process-of-oil-in-nigeria/]</ref>|512x512px]]
Crude oil, in its unrefined state, has almost no direct utility due to its highly complex molecular constitution. It exists fundamentally as a dense, complex mixture of hundreds of different hydrocarbons. The three basic components of crude oil are alkanes, cycloalkanes, and aromatics. The primary steps of chemical engineering within petroleum refineries are physical separation and chemical conversion. The first step separates the heterogeneous mixture into narrower, manageable fractions based on physical properties, and the second step upgrades these fractions into high-value, commercially viable products. This transformation from raw, unusable crude oil into high-value fuels relies on a sequence of thermal processes and complex catalytic reactions that manipulate molecular structures.<ref name=":6">Gary, J.H., Handwerk, J.H., Kaiser, M.J., & Geddes, D. (2007). Petroleum Refining: Technology and Economics, Fifth Edition (5th ed.). CRC Press. <nowiki>https://doi.org/10.4324/9780203907924</nowiki></ref>

The foundational stage of any refinery configuration is fractional distillation. It depends on the differential volatility and boiling points of the constituent hydrocarbons within crude oil. The process is commonly operationalized through the Atmospheric Distillation Unit: crude oil is preheated to approximately 350-400°C and pumped into the lowest and hottest level in the Fractional distillation tower. As the vaporized oil ascends through a series of distillation trays with temperature decreasing, it cools progressively. Hydrocarbons with lower boiling points condense at higher levels of the tower. This allows the continuous withdrawal of light fractions such as liquefied petroleum gas, naphtha, kerosene, and gas oil.<ref name=":6" />

Since the initial fractions obtained from atmospheric distillation are mostly the result of physical separation, they can't break the products into smaller molecules. Those distilled heavy molecules are hardly suitable for the commercial market. Thus, refineries rely heavily on cracking processes to convert these high-molecular-weight hydrocarbons into higher-value, lighter liquid fuels. This process involves the thermal or catalytic breaking of carbon-carbon covalent bonds in long-chain alkanes. Modern chemical engineering uses Fluid Catalytic Cracking (FCC) as the primary process. The market prefers this method due to its ability to maximize high-value gasoline yields from heavy gas oils. The efficiency of FCC is highly influenced by the use of highly active, acidic zeolite catalysts. Zeolite selectively accelerates secondary hydrocarbon cracking while minimizing unwanted coke formation. Alternatively, for middle distillates such as jet fuel and diesel, hydrocracking is used. This process takes place in a high-temperature, high-pressure, hydrogen-rich environment. Over catalysts, the hydrogen saturates aromatic rings and breaks the carbon chains.<ref name=":6" />

Reforming is another chemical process that changes a molecule's structure without altering the overall number of carbon atoms. This method is mainly used for straight-run naphtha, a distillation product. Straight-run naphtha has a suitable molecular size for vehicle engines, but the straight-chain alkanes it contains can cause knocking. Reforming uses chemical reactions to trigger isomerization, cyclization or dehydration of the straight chains. During catalytic reforming, a large amount of hydrogen is formed as a byproduct of dehydrogenation. This is great in the engineering industry, since hydrogen can be pumped straight to hydrotreating. Hydrotreating is a process for purifying. Crude oil naturally contains heteroatom impurities like sulphur, nitrogen, and heavy metals. With the purification process, SOx and NOx won't be released during burning, thereby preventing catalyst poisoning. Under high pressure and temperature, hydrogen can convert sulphur and nitrogen into H2S and NH3, separating the impurities completely.<ref name=":6" />

Through the physical separations and chemical alterations described above, crude oil ultimately becomes market products and plays an important role in the global economy. These outputs are broadly divided into three categories: transportation fuels, industrial specialty products, and petrochemical feedstocks. Transportation fuels such as gasoline, diesel, and kerosene sustain global logistics and transportation networks daily. They determine whether the international trade markets can function efficiently. Industrial specialty products like asphalt, which is extracted from heavy residues, play an indispensable role as the structural binder in global infrastructure development. Nevertheless, according to Levi et al. (2018), straight-run naphtha, serving as a petrochemical feedstock, has been a source for the global chemical industry. Through steam cracking, primary light olefins and aromatics are synthesized. Thus, downstream polymerization can convert them into ubiquitous materials such as polyethylene, polypropylene, and synthetic rubbers.<ref>Levi, P. G., & Cullen, J. M. (2018). Mapping Global Flows of Chemicals: From Fossil Fuel Feedstocks to Chemical Products. ''Environmental science & technology'', ''52''(4), 1725–1734. <nowiki>https://doi.org/10.1021/acs.est.7b04573</nowiki></ref>

== Environmental issues ==
When it comes to gas and oil extraction, environmental concerns are always on the table. Is the project sustainable? Will the extraction cause any irreparable damage to the Earth's environment? Are the operations negatively affecting other living beings' natural habitats? These are all the questions that geologists and engineers constantly ask themselves. To comprehensively assess environmental issues, both onshore and offshore oil and gas developments must be considered.

Onshore operations are raising the risks of induced earthquakes. Engineering techniques used in unconventional reservoirs, such as hydraulic fracturing and wastewater injection, alter subsurface pore-fluid pressure and reduce the shear strength of the original faults. This may increase the possibility of fault slippage, thus triggering seismic events. This phenomenon is particularly frequent in areas with active shale gas extraction. A case study in the Western Canada Sedimentary Basin (WCSB) in northeastern British Columbia, Canada, shows that the high-density hydraulic fracturing and fluid reinjection activities have led to a significant increase in regional background seismicity in recent years. To manage and minimize the damage caused by this issue, both geological and engineering knowledge are required. Since the fault slippage cannot be observed on the surface, a high-precision underground detector must be introduced. The seismic technology used for exploration can now serve as microseismic monitoring networks. Their ability to map subsurface fracture propagation in real time helps detect microseismic events and acoustic emissions. Collaborating with the Traffic Light Protocols (TLPs), which set the seismic magnitude thresholds, operations will be controlled automatically. Once the magnitude reaches a certain level, restrictions such as limiting injection rates or even mandatory shut-in will be imposed immediately.<ref>Pozzobon, C., Liu, Y., Kirkpatrick, J. D., Chesnaux, R., & Kang, M. (2023). Methane emissions from non-producing oil and gas wells and the potential role of seismic activity: A case study in Northeast British Columbia, Canada. Environmental Science & Technology, 57(51), 21673–21680. <nowiki>https://doi.org/10.1021/acs.est.3c06062</nowiki></ref>

The offshore deep-water oil and gas industry faces distinct issues that experts need to address. Exploration seismic technology relies on high-energy acoustic pulses. The noises can travel very far underwater and disrupt the behavioural patterns of some marine mammals that depend heavily on echolocation. The disruption might cause them to show abnormal behaviour, suffer hearing loss, or even get stranded. Spatial and temporal measures must be applied to prevent serious damage to these animals. Governments should establish avoidance rules and marine protected areas to regulate interactions between the extraction team and marine life. Restricted windows must be strictly obeyed during migration and breeding seasons. Minimum buffer zones should be built around sensitive ecological communities to isolate direct physical and acoustic impact.<ref>Cordes, E. E., Jones, D. O. B., Schlacher, T. A., Amon, D. J., Bernardino, A. F., Brooke, S., Carney, R., DeLeo, D. M., et al. (2016). Environmental impacts of the deep-water oil and gas industry: A review to guide management strategies. ''Frontiers in Environmental Science, 4'', Article 58. <nowiki>https://doi.org/10.3389/fenvs.2016.00058</nowiki></ref> Furthermore, the produced water extracted with crude oil is highly toxic and will casue serious environmental consequences if discharged directly into the ocean. It contains a high concentration of salt, toxic dissolved heavy metals and polycyclic aromatic hydrocarbons. Bioaccumulation and chronic toxicity can negatively affect every step of the marine food chain and damage ecosystems. Multi-step purification must be applied using engineering methods such as physical sedimentation, membrane separation, and advanced oxidation. Systematic inspection will ensure compliance with the standards for discharge or reinjection.<ref>Fakhru’l‑Razi, A., Pendashteh, A., Abdullah, L. C., Biak, D. R. A., Madaeni, S. S., & Abidin, Z. Z. (2009). Produced water treatment and reuse: A review. Journal of Hazardous Materials, 170(2–3), 530–551. <nowiki>https://doi.org/10.1016/j.jhazmat.2009.05.044</nowiki></ref>[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

== Conclusion, Evaluation of the Connections, and Personal Appreciation ==

== Breakdown of Group Contributions and AI Statement ==

=== Breakdown of group contributions: ===
Marijke:

* Introduction to Petroleum Systems
* Geological Formation
* Reservoir Quality

Jack:

* Oil and Gas Exploration: Seismic Technology
* Oil and Gas Extraction: How Geology Determines Engineering Decisions
Keming:
* Chemical Engineering and Petroleum Products
* Environmental Issues

=== AI Statement: ===
AI tools were used to support brainstorming ideas and to delegate portions within the group. AI-generated images are used and cited. All final written content have been created and reviewed by all group members.

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-18T01:21:00Z

KemingWu: /* Chemical Engineering and Petroleum Products */

==Introduction to Petroleum Systems==

Oil and natural gas are among the most important geological resources utilized by modern society. This industry fuels the global economy and energy is used for electricity, transportation, and industrial manufacturing. The oil and gas industry is considered in three main sectors<ref name=":3">{{Cite web|last=McClay|first=R.|date=2025-10-12|title=Understanding the Oil and Gas Industry: A Comprehensive Overview|url=https://www.investopedia.com/investing/oil-gas-industry-overview/|url-status=live|website=Investopedia}}</ref>:
{| class="wikitable"
|'''Upstream Sector'''
|'''Midstream Sector'''
|'''Downstream Sector'''
|-
|Include exploration and production. Companies drill for oil and gas.
|Include transportation and usage. Companies handle transit to oil refineries.
|Include refining and distribution. Companies produce refined oil and gas and sell it as gasoline and jet fuel.
|}
Oil and gas consists of hydrocarbons that form naturally within Earth’s crust over millions of years. Organic material derived from plants, animals, and microbes accumulate within depositions, and over geological time, becomes incorporated into sedimentary rocks. These rocks include sandstone, limestone, and shale, and form in ancient oceans. Burial beneath additional sediment subjects organic matter to high temperatures and pressures, leading to the formation of oil and natural gas within the subsurface<ref name=":3" />.

Hydrocarbons may migrate through porous and permeable sedimentary rocks, as they are less dense than surrounding water. An oil and gas reservoir is created when migrating hydrocarbons reach a barrier. These are the types of reservoirs that are used by the petroleum industry by drilling through overlying rocks into the subsurface reservoir<ref name=":3" />.

The petroleum industry is closely related to chemistry and engineering. Geology identifies the source rocks, reservoirs, seals, and migration pathways required for hydrocarbon accumulation, while chemistry helps explain the transformation into petroleum under changing pressure and temperatures. This directly influences engineering decisions related to exploration, production, and resource development. Petroleum systems demonstrate how geological processes create conditions for both chemical and engineering applications.

== Geological Formation ==
The occurrence of oil and gas within the Earth’s crust is demonstrated by a geological framework known as the Total Petroleum System<ref name=":4">{{Cite journal|last=Magoon|first=L. B.|last2=Schmoker|first2=J. W.|date=2000|title=The Total Petroleum System - The Natural Fluid Network that Constrains the Assessment Unit|url=https://pubs.usgs.gov/dds/dds-060/chaps/PS.pdf|journal=United States Geological Survey|pages=1-20}}</ref>. This is the basis for assessing hydrocarbon resources, as it considers both geological elements and processes required for the accumulations to exist. A petroleum system consists of four essential geological elements; source rock, reservoir rock, seal rock, and overburden rock. The essential processes of the Total Petroleum System are generation, migration, accumulation, and trap formation. The first stage of oil and gas formation is hydrocarbon generation within a source rock, defined as the origin of petroleum within the system. The “pod of active source rock” are adjacent source rocks that are responsible for generating hydrocarbons. Under high temperature and pressure conditions, hydrocarbons are expelled from the source rock and into surrounding rock units<ref name=":4" />.

Once generated, hydrocarbons migrate through the subsurface. A petroleum system requires pathways that allow the oil and gas to move from the source rock and into geological formations that can store hydrocarbons. Without migration pathways, generated hydrocarbons would remain trapped within the source rock and accumulations would not form<ref name=":4" />.
[[File:Figure 1. Geological Cross-Section of an OIl and Gas Reservoir.png|thumb|514x514px|Figure 1. Geological Cross-Section of an Oil and Gas Reservoir]]
Hydrocarbons accumulate within the pores of reservoir rocks. Reservoir rocks are essential to the petroleum system since they provide space for hydrocarbon storage. Reservoir characterization studies evaluate properties including porosity and permeability; qualities that dictate the amount of available hydrocarbon storage as well as the ease that fluid can move within the rock. Reservoir rocks with high porosity and permeability are considered more effective at storing hydrocarbons<ref name=":5" />.

For hydrocarbons to remain within a reservoir, a seal rock must also be present. Seal rocks are identified as one of the four essential petroleum system elements because they act as barriers that restrict fluid movement and prevent hydrocarbons from escaping. Additionally, trap formation must occur to retain migrating hydrocarbons. The process of accumulation and trap formation are together required to create and preserve petroleum deposits<ref name=":4" />.

The final essential element of a petroleum system is overburden rock. Overburden refers to the layers of sediment and rock that accumulate above the source rock and reservoir rock over geological time. As additional sediments are deposited, the increasing thickness of overburden subjects underlying rocks to higher temperatures and processes during burial. These conditions influence the thermal maturity of source rocks and play a crucial role in hydrocarbon generation. Therefore, the thickness and burial history over the overburden can be used by geologists to determine whether or not the source rocks have reached the temperature and pressure conditions that are necessary for oil and gas formation<ref name=":4" />.

== Reservoir Quality ==

The presence of a petroleum system alone does not guarantee that hydrocarbons can be recovered economically. Reservoir quality is primarily determined by porosity and permeability, which are considered the fundamental factors of the petroleum reservoir viability. Porosity is the amount of pore space available within a rock for hydrocarbon storage, while permeability describes the degree to which fluids can move through connected pore networks. Reservoir rocks may contain significant pore space but still be considered poor-quality if pore connections are limited. Consequently, both properties must be evaluated when assessing whether or not a reservoir is considered commercially viable. Other important factors of reservoir quality include depositional environment, sediment provenance, weathering, compaction, dissolution, burial depth, pressure, and structural deformation. Since these controls interact over millions of years, reservoir quality reflects cumulative effects, looking back to initial sediment<ref name=":5" />.

One of the most important controls on reservoir quality is the depositional environment in which the sediment was originally deposited. The primary composition of sediment strongly influences the future evolution of reservoir rocks. In sandstone reservoirs, factors such as the source-area geology, climate, topography, and grain size all affect the resulting rock properties. These factors all influence pore space, and therefore impact reservoir quality. Sediments deposited in shallow marine environments often develop better reservoir properties because they tend to be cleaner and contain fewer fine materials that can reduce pore connections. On the other hand, sediments deposited in low-energy environments may contain more clay and silt, which can negatively affect reservoir quality. Well-sorted sediments generally have more interconnected pores than poorly sorted sediments that contain fine grain matrix material<ref name=":5" />.

Different lithologies also respond differently to geological processes. Sandstone reservoirs are among the most common hydrocarbon reservoirs because they can preserve great porosity between sediment grains. Carbonate reservoirs, including limestone and dolostone, often undergo many diagenetic changes through processes such as dissolution, recrystallization, and dolomitization due to their greater chemical reactivity. Rather than relying solely on primary pore space, carbonate reservoirs often develop secondary porosity through diagenesis and fracturing. As a result, both sandstone and carbonate reservoirs often have the capacity to contain hydrocarbons, although having very different pore systems and geological histories<ref name=":5" />.

Following deposition, sediment undergoes diagenesis when physical and chemical changes occur as the sediment is transformed into sedimentary rock. Important stages in reservoir evolution include eodiagenesis (early burial diagenesis), mesodiagenesis (burial diagenesis), and telodiagenesis (uplift-related changes)<ref name=":5" />. During these stages, sediments experience compaction, dissolution, mineral replacement, fracturing, and fluid interactions that can significantly alter reservoir properties. These diagenetic processes can reduce reservoir quality. Compaction during burial decreases pore space as sediment gains become more tightly packed. Chemical compaction and pressure solution may further reduce porosity. Minerals such as quartz, calcite, dolomite, and clay can fill pore spaces and restrict fluid movement. Quartz cementation is identified as one of the most important pore-filling processes in deep buried sandstone reservoirs because of the way it reduces the amount of available pore space progressively. Clay mineral does so similarly and may significantly decrease permeability by blocking pores and restricting fluid flow <ref name=":5">{{Cite journal|last=Worden|first=R. H.|last2=Armitage|first2=P. J.|last3=Butcher|first3=A. R.|last4=Churchill|first4=J. M.|last5=Csoma|first5=A. E.|last6=Hollis|first6=C.|last7=Lander|first7=R. H.|last8=Omma|first8=J. E.|date=2018|title=Petroleum reservoir quality prediction: overview and contrasting approaches from sandstone and carbonate communities|url=https://doi.org/10.1144/SP435.21|journal=Geological Society|volume=435|pages=1-31}}</ref>.

Reservoir quality is not solely determined by burial and porosity. The final characteristics of a reservoir are reflected by the preservation of pore space. Reservoirs with similar depositional origination may exhibit very different porosity and permeability depending on their diagenetic history and the geological conditions they experienced during burial and uplift<ref name=":5" />.
== Oil and Gas Exploration: Seismic Technology ==

Now we know the importance of oil and gas to our society, and how they were formed, the next question is where to locate them. Since reservoirs are below the surface, geologists cannot directly see where they are before drilling. This makes drilling a gamble, and that's where seismic reflection technology contributes to lowering the risk. It works as a tool that helps geologists to create an image of what is beneath the surface before they decide where to drill <ref name=":0">{{Cite journal|last=Mohammed|first=Farfour|date=2016-05-01|title=A review on multicomponent seismology: A potential seismic application for reservoir characterization|url=https://www.sciencedirect.com/science/article/pii/S2090123215001125|journal=Journal of Advanced Research|volume=3|pages=515-524}}</ref>.[[File:Seismic_Survey_and_Mechanism.png|thumb|left|500x500px|Figure 1. Seismic Technology and Mechanism for oil Exploration]]The working principle behind seismic is to use energy waves to explore underground rock layers. During a survey, energy waves are sent into the ground. When waves hit the boundaries between rock layers, some of the energy bounces back to the surface, while some goes further. Receivers then pick up these reflected waves and give information about the depth, shape and arrangement of subsurface layers by analyzing the different waves using the pre-known typical rock’s density and acoustic impedance. After processing, the data can be shown as profiles or 3D seismic images <ref>{{Cite journal|last=Ilya|first=Tsvankin|date=2010-09-01|title=Seismic anisotropy in exploration and reservoir characterization: An overview|url=https://www.researchgate.net/publication/228633261_Seismic_anisotropy_in_exploration_and_reservoir_characterization_An_overview|journal=Geophysics|volume=75}}</ref>.

This is essential because oil and gas need geological structures to build up, and seismic interpretation helps identify these structures. For example, folds show up as layers in seismic images. If the fold creates an anticline, oil and gas might move upward and get trapped near the top. Faults can be spotted when rock layers are broken or displaced. Faults can create traps but might let hydrocarbons escape as well if they aren't sealed properly. So seismic data are not just used to "find oil", they help us understand if subsurface geology has the right structure to store oil and gas<ref>{{Cite journal|last=Lawson|first=M.|date=2018-02-19|title=Geochemical applications in petroleum systems analysis: New constraints and the power of integration|url=https://www.researchgate.net/publication/323282762_Geochemical_applications_in_petroleum_systems_analysis_New_constraints_and_the_power_of_integration|journal=Geological Society, London, Special Publications|volume=468|pages=6}}</ref> . More than locating the reservoir, seismic technology also helps geologists understand its geometry. This includes the shape, thickness, depth and continuity of a reservoir. This matters because a reservoir can be located but not profitable for business. With current technology and the purpose of maximizing the future extraction, geologists are targeting large and continuous reservoirs rather than thin and isolated ones. Seismic data can help pinpoint the drilling target by showing where the reservoir might be thicker or larger<ref name=":0" /> .

An exploration workflow usually starts with a regional study. The first step is for geologists to determine if the region has a petroleum system with possible traps that contain oil. Then there are follow-up seismic surveys to get evidence and more information. Next, geoscientists interpret the data to distinguish geological structures and possible drilling targets. These decisions are assisted by other data, such as core samples. Finally, drilling locations are chosen based on different criteria <ref name=":1">{{Cite journal|last=Ma|first=Yuan Zhe|date=2011-01-01|title=Uncertainty Analysis in Reservoir Characterization and Management: How Much Should We Know About What We Don't Know?|url=https://pubs.geoscienceworld.org/aapg/books/edited-volume/1248/chapter-abstract/107059711/Uncertainty-Analysis-in-Reservoir-Characterization?redirectedFrom=fulltext|journal=AAPG Memoir|volume=1|pages=15}}</ref>.

However, seismic technology is not perfect. As an imaging technique that relies on the reflection of waves, some thin reservoirs or structures can be hard to detect. Also, seismic data cannot directly show the oil and gas but uses structures to infer their existence. Based on this limitation, seismic technology is more like a tool that reduces drilling risk than eliminates all uncertainties <ref>Saad, M. R., & Jadeer, A.-S. (2022). ''Seismic Method for Exploration Oil and Gas Reservoirs''. <nowiki>https://doi.org/10.1007/978-981-99-1964-2_89</nowiki></ref>.

== Oil and Gas Extraction: How Geology Determines Engineering Decisions ==
Once an oil reservoir is proven as continuous and profitable, geology still plays a role in deciding how to extract the resources. In a word, engineering decisions and extraction methods are based on how the subsurface looks and how fluids move through the rock.

Engineers need more geology information before deciding where to drill. They want to know the depth of the potential drilling trajectory, the thickness of the oil reservoir, and the fluid contacts of the reservoir to optimize the performance. For example, a rich oil-bearing zone in the reservoir should be the highest priority to place the well nearby. However, if the zone is disrupted by some faults, then engineers and geologists must determine whether these faults connect to parts of the reservoir or cut it into separate parts. Moreover, if the production well is too close to a water or gas zone, a water or gas breakthrough is likely to happen and reduce oil production. In a real-world case, a breakthrough can easily turn a high-production well into a shut-down.
[[File:Reservori_Simulation_Model.jpg|thumb|Figure 2. The reservoir modeling workflow showing the sequence of stages in data acquisition and interpretation<ref name=":2">Abel, M., Garcia, L., Lorenzatti, A., & De Ros, L. (2010, October 26). ''SEMANTIC INTEROPERABILITY IN THE PETROLEUM CHAIN: THE CONTRIBUTION OF ONTOLOGICAL ANALYSIS''.</ref>|549x549px]]Reservoir simulation is a great tool to use in oil extraction, just like how seismic technology assists oil exploration. A reservoir model is a digital version of a reservoir with a vivid representation of reservoir structures and various relevant properties like pressure, permeability, porosity, and saturation of each phase. Engineers use this model to predict how the reservoir might behave during production. For instance, the model can estimate production rates, pressure changes, and any potential water cut. It can also achieve optimization on certain jobs, like comparing different production plans and well placement strategies. Since the model is built purely based on geological data, its quality varies depending on how well the regional geology is captured and understood, and this can also be a limitation of the reservoir model <ref name=":2" /><ref>Sambo, C., Iferobia, C. C., Babasafari, A. A., Rezaei, S., & Akanni, O. A. (2020). The Role of Time Lapse(4D) Seismic Technology as Reservoir Monitoring and Surveillance Tool: A Comprehensive Review. ''Journal of Natural Gas Science and Engineering'', ''80'', 103312. <nowiki>https://doi.org/10.1016/j.jngse.2020.103312</nowiki></ref>.

Since there are many different types of reservoirs, extraction methods have also been developed differently to achieve efficient production for each case. And they can be separated under two main reservoir types: conventional and unconventional.
{| class="wikitable"
|+
!Reservoir Type
!Geological Characteristics
!Main Extraction Methods
!Engineering
Reason
|-
|Conventional reservoirs
|High permeability and porosity for fluids to flow naturally toward the well through connected pore spaces
|Primary production relies on natural reservoir pressure and secondary recovery methods like water injection are used to maintain the pressure
|Maintain and increase reservoir pressure to improve flow toward production wells
|-
|Unconventional reservoirs
|Low permeability so fluids are trapped in rocks or exist as highly viscous bitumen
|Horizontal drilling and hydraulic fracturing are commonly used for shale gas and tight oil
For deep oil sands, steam-assisted gravity drainage can be used by injecting steam underground to heat bitumen and lower the viscousity
|Create flow pathways to make hydrocarbons mobile enough to be produced
|}
Overall, geology has a strong influence on engineering decisions in oil and gas extraction. Geology informs engineers to know the reservoir quality, what extraction methodology can be applied, and what risks might exist during production. Geological information has also been integrated into reservoir models to provide a more in-depth understanding and optimization. Oil extraction is not just about improving equipment and technology, it is also a process in which geological knowledge is applied with engineering decisions.

== Chemical Engineering and Petroleum Products ==
[[File:Fractional Distillation.jpg|thumb|Fractional Distillation Process of Crude Oil<ref>[https://wigmoretrading.com/what-is-the-fractional-distillation-process-of-oil-in-nigeria/]</ref>|512x512px]]
Crude oil, in its unrefined state, has almost no direct utility due to its highly complex molecular constitution. It exists fundamentally as a dense, complex mixture of hundreds of different hydrocarbons. The three basic components of crude oil are alkanes, cycloalkanes, and aromatics. The primary steps of chemical engineering within petroleum refineries are physical separation and chemical conversion. The first step separates the heterogeneous mixture into narrower, manageable fractions based on physical properties, and the second step upgrades these fractions into high-value, commercially viable products. This transformation from raw, unusable crude oil into high-value fuels relies on a sequence of thermal processes and complex catalytic reactions that manipulate molecular structures.<ref name=":6">Gary, J.H., Handwerk, J.H., Kaiser, M.J., & Geddes, D. (2007). Petroleum Refining: Technology and Economics, Fifth Edition (5th ed.). CRC Press. <nowiki>https://doi.org/10.4324/9780203907924</nowiki></ref>

The foundational stage of any refinery configuration is fractional distillation. It depends on the differential volatility and boiling points of the constituent hydrocarbons within crude oil. The process is commonly operationalized through the Atmospheric Distillation Unit: crude oil is preheated to approximately 350-400°C and pumped into the lowest and hottest level in the Fractional distillation tower. As the vaporized oil ascends through a series of distillation trays with temperature decreasing, it cools progressively. Hydrocarbons with lower boiling points condense at higher levels of the tower. This allows the continuous withdrawal of light fractions such as liquefied petroleum gas, naphtha, kerosene, and gas oil.<ref name=":6" />

Since the initial fractions obtained from atmospheric distillation are mostly the result of physical separation, they can't break the products into smaller molecules. Those distilled heavy molecules are hardly suitable for the commercial market. Thus, refineries rely heavily on cracking processes to convert these high-molecular-weight hydrocarbons into higher-value, lighter liquid fuels. This process involves the thermal or catalytic breaking of carbon-carbon covalent bonds in long-chain alkanes. Modern chemical engineering uses Fluid Catalytic Cracking (FCC) as the primary process. The market prefers this method due to its ability to maximize high-value gasoline yields from heavy gas oils. The efficiency of FCC is highly influenced by the use of highly active, acidic zeolite catalysts. Zeolite selectively accelerates secondary hydrocarbon cracking while minimizing unwanted coke formation. Alternatively, for middle distillates such as jet fuel and diesel, hydrocracking is used. This process takes place in a high-temperature, high-pressure, hydrogen-rich environment. Over catalysts, the hydrogen saturates aromatic rings and breaks the carbon chains.<ref name=":6" />

Reforming is another chemical process that changes a molecule's structure without altering the overall number of carbon atoms. This method is mainly used for straight-run naphtha, a distillation product. Straight-run naphtha has a suitable molecular size for vehicle engines, but the straight-chain alkanes it contains can cause knocking. Reforming uses chemical reactions to trigger isomerization, cyclization or dehydration of the straight chains. During catalytic reforming, a large amount of hydrogen is formed as a byproduct of dehydrogenation. This is great in the engineering industry, since hydrogen can be pumped straight to hydrotreating. Hydrotreating is a process for purifying. Crude oil naturally contains heteroatom impurities like sulphur, nitrogen, and heavy metals. With the purification process, SOx and NOx won't be released during burning, thereby preventing catalyst poisoning. Under high pressure and temperature, hydrogen can convert sulphur and nitrogen into H2S and NH3, separating the impurities completely.<ref name=":6" />

Through the physical separations and chemical alterations described above, crude oil ultimately becomes market products and plays an important role in the global economy. These outputs are broadly divided into three categories: transportation fuels, industrial specialty products, and petrochemical feedstocks. Transportation fuels such as gasoline, diesel, and kerosene sustain global logistics and transportation networks daily. They determine whether the international trade markets can function efficiently. Industrial specialty products like asphalt, which is extracted from heavy residues, play an indispensable role as the structural binder in global infrastructure development. Nevertheless, according to Levi et al. (2018), straight-run naphtha, serving as a petrochemical feedstock, has been a source for the global chemical industry. Through steam cracking, primary light olefins and aromatics are synthesized. Thus, downstream polymerization can convert them into ubiquitous materials such as polyethylene, polypropylene, and synthetic rubbers.<ref>Levi, P. G., & Cullen, J. M. (2018). Mapping Global Flows of Chemicals: From Fossil Fuel Feedstocks to Chemical Products. ''Environmental science & technology'', ''52''(4), 1725–1734. <nowiki>https://doi.org/10.1021/acs.est.7b04573</nowiki></ref>

== Environmental issues ==
When it comes to gas and oil extraction, environmental concerns are always on the table. Is the project sustainable? Will the extraction cause any irreparable damage to the Earth's environment? Are the operations negatively affecting other living beings' natural habitats? These are all the questions that geologists and engineers constantly ask themselves. To comprehensively assess environmental issues, both onshore and offshore oil and gas developments must be considered.

Onshore operations are raising the risks of induced earthquakes. Engineering techniques used in unconventional reservoirs, such as hydraulic fracturing and wastewater injection, alter subsurface pore-fluid pressure and reduce the shear strength of the original faults. This may increase the possibility of fault slippage, thus triggering seismic events. This phenomenon is particularly frequent in areas with active shale gas extraction. A case study in the Western Canada Sedimentary Basin (WCSB) in northeastern British Columbia, Canada, shows that the high-density hydraulic fracturing and fluid reinjection activities have led to a significant increase in regional background seismicity in recent years. To manage and minimize the damage caused by this issue, both geological and engineering knowledge are required. Since the fault slippage cannot be observed on the surface, a high-precision underground detector must be introduced. The seismic technology used for exploration can now serve as microseismic monitoring networks. Their ability to map subsurface fracture propagation in real time helps detect microseismic events and acoustic emissions. Collaborating with the Traffic Light Protocols (TLPs), which set the seismic magnitude thresholds, operations will be controlled automatically. Once the magnitude reaches a certain level, restrictions such as limiting injection rates or even mandatory shut-in will be imposed immediately.<ref>Pozzobon, C., Liu, Y., Kirkpatrick, J. D., Chesnaux, R., & Kang, M. (2023). Methane emissions from non-producing oil and gas wells and the potential role of seismic activity: A case study in Northeast British Columbia, Canada. Environmental Science & Technology, 57(51), 21673–21680. <nowiki>https://doi.org/10.1021/acs.est.3c06062</nowiki></ref>

The offshore deep-water oil and gas industry faces distinct issues that experts need to address. Exploration seismic technology relies on high-energy acoustic pulses. The noises can travel very far underwater and disrupt the behavioural patterns of some marine mammals that depend heavily on echolocation. The disruption might cause them to show abnormal behaviour, suffer hearing loss, or even get stranded. Spatial and temporal measures must be applied to prevent serious damage to these animals. Governments should establish avoidance rules and marine protected areas to regulate interactions between the extraction team and marine life. Restricted windows must be strictly obeyed during migration and breeding seasons. Minimum buffer zones should be built around sensitive ecological communities to isolate direct physical and acoustic impact.<ref>Cordes, E. E., Jones, D. O. B., Schlacher, T. A., Amon, D. J., Bernardino, A. F., Brooke, S., Carney, R., DeLeo, D. M., et al. (2016). Environmental impacts of the deep-water oil and gas industry: A review to guide management strategies. ''Frontiers in Environmental Science, 4'', Article 58. <nowiki>https://doi.org/10.3389/fenvs.2016.00058</nowiki></ref> Furthermore, the produced water extracted with crude oil is highly toxic and will casue serious environmental consequences if discharged directly into the ocean. It contains a high concentration of salt, toxic dissolved heavy metals and polycyclic aromatic hydrocarbons. Bioaccumulation and chronic toxicity can negatively affect every step of the marine food chain and damage ecosystems. Multi-step purification must be applied using engineering methods such as physical sedimentation, membrane separation, and advanced oxidation. Systematic inspection will ensure compliance with the standards for discharge or reinjection.<ref>Fakhru’l‑Razi, A., Pendashteh, A., Abdullah, L. C., Biak, D. R. A., Madaeni, S. S., & Abidin, Z. Z. (2009). Produced water treatment and reuse: A review. Journal of Hazardous Materials, 170(2–3), 530–551. <nowiki>https://doi.org/10.1016/j.jhazmat.2009.05.044</nowiki></ref>[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Conclusion / Your Evaluation of the Connections==

=== Conclusion: ===

=== Breakdown of group contributions: ===
Marijke:

* Introduction to Petroleum Systems
* Geological Formation
* Reservoir Quality

Jack:

* Oil and Gas Exploration: Seismic Technology
* Oil and Gas Extraction: How Geology Determines Engineering Decisions
Keming:
* Chemical Engineering and Petroleum Products
* Environmental Issues

=== AI Statement: ===
AI tools were used to support brainstorming ideas and to delegate portions within the group. AI-generated images are used and cited. All final written content have been created and reviewed by all group members.

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-18T01:13:43Z

KemingWu: /* Chemical Engineering and Petroleum Products */

==Introduction to Petroleum Systems==

Oil and natural gas are among the most important geological resources utilized by modern society. This industry fuels the global economy and energy is used for electricity, transportation, and industrial manufacturing. The oil and gas industry is considered in three main sectors<ref name=":3">{{Cite web|last=McClay|first=R.|date=2025-10-12|title=Understanding the Oil and Gas Industry: A Comprehensive Overview|url=https://www.investopedia.com/investing/oil-gas-industry-overview/|url-status=live|website=Investopedia}}</ref>:
{| class="wikitable"
|'''Upstream Sector'''
|'''Midstream Sector'''
|'''Downstream Sector'''
|-
|Include exploration and production. Companies drill for oil and gas.
|Include transportation and usage. Companies handle transit to oil refineries.
|Include refining and distribution. Companies produce refined oil and gas and sell it as gasoline and jet fuel.
|}
Oil and gas consists of hydrocarbons that form naturally within Earth’s crust over millions of years. Organic material derived from plants, animals, and microbes accumulate within depositions, and over geological time, becomes incorporated into sedimentary rocks. These rocks include sandstone, limestone, and shale, and form in ancient oceans. Burial beneath additional sediment subjects organic matter to high temperatures and pressures, leading to the formation of oil and natural gas within the subsurface<ref name=":3" />.

Hydrocarbons may migrate through porous and permeable sedimentary rocks, as they are less dense than surrounding water. An oil and gas reservoir is created when migrating hydrocarbons reach a barrier. These are the types of reservoirs that are used by the petroleum industry by drilling through overlying rocks into the subsurface reservoir<ref name=":3" />.

The petroleum industry is closely related to chemistry and engineering. Geology identifies the source rocks, reservoirs, seals, and migration pathways required for hydrocarbon accumulation, while chemistry helps explain the transformation into petroleum under changing pressure and temperatures. This directly influences engineering decisions related to exploration, production, and resource development. Petroleum systems demonstrate how geological processes create conditions for both chemical and engineering applications.

== Geological Formation ==
The occurrence of oil and gas within the Earth’s crust is demonstrated by a geological framework known as the Total Petroleum System<ref name=":4">{{Cite journal|last=Magoon|first=L. B.|last2=Schmoker|first2=J. W.|date=2000|title=The Total Petroleum System - The Natural Fluid Network that Constrains the Assessment Unit|url=https://pubs.usgs.gov/dds/dds-060/chaps/PS.pdf|journal=United States Geological Survey|pages=1-20}}</ref>. This is the basis for assessing hydrocarbon resources, as it considers both geological elements and processes required for the accumulations to exist. A petroleum system consists of four essential geological elements; source rock, reservoir rock, seal rock, and overburden rock. The essential processes of the Total Petroleum System are generation, migration, accumulation, and trap formation. The first stage of oil and gas formation is hydrocarbon generation within a source rock, defined as the origin of petroleum within the system. The “pod of active source rock” are adjacent source rocks that are responsible for generating hydrocarbons. Under high temperature and pressure conditions, hydrocarbons are expelled from the source rock and into surrounding rock units<ref name=":4" />.

Once generated, hydrocarbons migrate through the subsurface. A petroleum system requires pathways that allow the oil and gas to move from the source rock and into geological formations that can store hydrocarbons. Without migration pathways, generated hydrocarbons would remain trapped within the source rock and accumulations would not form<ref name=":4" />.
[[File:Figure 1. Geological Cross-Section of an OIl and Gas Reservoir.png|thumb|514x514px|Figure 1. Geological Cross-Section of an Oil and Gas Reservoir]]
Hydrocarbons accumulate within the pores of reservoir rocks. Reservoir rocks are essential to the petroleum system since they provide space for hydrocarbon storage. Reservoir characterization studies evaluate properties including porosity and permeability; qualities that dictate the amount of available hydrocarbon storage as well as the ease that fluid can move within the rock. Reservoir rocks with high porosity and permeability are considered more effective at storing hydrocarbons<ref name=":5" />.

For hydrocarbons to remain within a reservoir, a seal rock must also be present. Seal rocks are identified as one of the four essential petroleum system elements because they act as barriers that restrict fluid movement and prevent hydrocarbons from escaping. Additionally, trap formation must occur to retain migrating hydrocarbons. The process of accumulation and trap formation are together required to create and preserve petroleum deposits<ref name=":4" />.

The final essential element of a petroleum system is overburden rock. Overburden refers to the layers of sediment and rock that accumulate above the source rock and reservoir rock over geological time. As additional sediments are deposited, the increasing thickness of overburden subjects underlying rocks to higher temperatures and processes during burial. These conditions influence the thermal maturity of source rocks and play a crucial role in hydrocarbon generation. Therefore, the thickness and burial history over the overburden can be used by geologists to determine whether or not the source rocks have reached the temperature and pressure conditions that are necessary for oil and gas formation<ref name=":4" />.

== Reservoir Quality ==

The presence of a petroleum system alone does not guarantee that hydrocarbons can be recovered economically. Reservoir quality is primarily determined by porosity and permeability, which are considered the fundamental factors of the petroleum reservoir viability. Porosity is the amount of pore space available within a rock for hydrocarbon storage, while permeability describes the degree to which fluids can move through connected pore networks. Reservoir rocks may contain significant pore space but still be considered poor-quality if pore connections are limited. Consequently, both properties must be evaluated when assessing whether or not a reservoir is considered commercially viable. Other important factors of reservoir quality include depositional environment, sediment provenance, weathering, compaction, dissolution, burial depth, pressure, and structural deformation. Since these controls interact over millions of years, reservoir quality reflects cumulative effects, looking back to initial sediment<ref name=":5" />.

One of the most important controls on reservoir quality is the depositional environment in which the sediment was originally deposited. The primary composition of sediment strongly influences the future evolution of reservoir rocks. In sandstone reservoirs, factors such as the source-area geology, climate, topography, and grain size all affect the resulting rock properties. These factors all influence pore space, and therefore impact reservoir quality. Sediments deposited in shallow marine environments often develop better reservoir properties because they tend to be cleaner and contain fewer fine materials that can reduce pore connections. On the other hand, sediments deposited in low-energy environments may contain more clay and silt, which can negatively affect reservoir quality. Well-sorted sediments generally have more interconnected pores than poorly sorted sediments that contain fine grain matrix material<ref name=":5" />.

Different lithologies also respond differently to geological processes. Sandstone reservoirs are among the most common hydrocarbon reservoirs because they can preserve great porosity between sediment grains. Carbonate reservoirs, including limestone and dolostone, often undergo many diagenetic changes through processes such as dissolution, recrystallization, and dolomitization due to their greater chemical reactivity. Rather than relying solely on primary pore space, carbonate reservoirs often develop secondary porosity through diagenesis and fracturing. As a result, both sandstone and carbonate reservoirs often have the capacity to contain hydrocarbons, although having very different pore systems and geological histories<ref name=":5" />.

Following deposition, sediment undergoes diagenesis when physical and chemical changes occur as the sediment is transformed into sedimentary rock. Important stages in reservoir evolution include eodiagenesis (early burial diagenesis), mesodiagenesis (burial diagenesis), and telodiagenesis (uplift-related changes)<ref name=":5" />. During these stages, sediments experience compaction, dissolution, mineral replacement, fracturing, and fluid interactions that can significantly alter reservoir properties. These diagenetic processes can reduce reservoir quality. Compaction during burial decreases pore space as sediment gains become more tightly packed. Chemical compaction and pressure solution may further reduce porosity. Minerals such as quartz, calcite, dolomite, and clay can fill pore spaces and restrict fluid movement. Quartz cementation is identified as one of the most important pore-filling processes in deep buried sandstone reservoirs because of the way it reduces the amount of available pore space progressively. Clay mineral does so similarly and may significantly decrease permeability by blocking pores and restricting fluid flow <ref name=":5">{{Cite journal|last=Worden|first=R. H.|last2=Armitage|first2=P. J.|last3=Butcher|first3=A. R.|last4=Churchill|first4=J. M.|last5=Csoma|first5=A. E.|last6=Hollis|first6=C.|last7=Lander|first7=R. H.|last8=Omma|first8=J. E.|date=2018|title=Petroleum reservoir quality prediction: overview and contrasting approaches from sandstone and carbonate communities|url=https://doi.org/10.1144/SP435.21|journal=Geological Society|volume=435|pages=1-31}}</ref>.

Reservoir quality is not solely determined by burial and porosity. The final characteristics of a reservoir are reflected by the preservation of pore space. Reservoirs with similar depositional origination may exhibit very different porosity and permeability depending on their diagenetic history and the geological conditions they experienced during burial and uplift<ref name=":5" />.
== Oil and Gas Exploration: Seismic Technology ==

Now we know the importance of oil and gas to our society, and how they were formed, the next question is where to locate them. Since reservoirs are below the surface, geologists cannot directly see where they are before drilling. This makes drilling a gamble, and that's where seismic reflection technology contributes to lowering the risk. It works as a tool that helps geologists to create an image of what is beneath the surface before they decide where to drill <ref name=":0">{{Cite journal|last=Mohammed|first=Farfour|date=2016-05-01|title=A review on multicomponent seismology: A potential seismic application for reservoir characterization|url=https://www.sciencedirect.com/science/article/pii/S2090123215001125|journal=Journal of Advanced Research|volume=3|pages=515-524}}</ref>.[[File:Seismic_Survey_and_Mechanism.png|thumb|left|500x500px|Figure 1. Seismic Technology and Mechanism for oil Exploration]]The working principle behind seismic is to use energy waves to explore underground rock layers. During a survey, energy waves are sent into the ground. When waves hit the boundaries between rock layers, some of the energy bounces back to the surface, while some goes further. Receivers then pick up these reflected waves and give information about the depth, shape and arrangement of subsurface layers by analyzing the different waves using the pre-known typical rock’s density and acoustic impedance. After processing, the data can be shown as profiles or 3D seismic images <ref>{{Cite journal|last=Ilya|first=Tsvankin|date=2010-09-01|title=Seismic anisotropy in exploration and reservoir characterization: An overview|url=https://www.researchgate.net/publication/228633261_Seismic_anisotropy_in_exploration_and_reservoir_characterization_An_overview|journal=Geophysics|volume=75}}</ref>.

This is essential because oil and gas need geological structures to build up, and seismic interpretation helps identify these structures. For example, folds show up as layers in seismic images. If the fold creates an anticline, oil and gas might move upward and get trapped near the top. Faults can be spotted when rock layers are broken or displaced. Faults can create traps but might let hydrocarbons escape as well if they aren't sealed properly. So seismic data are not just used to "find oil", they help us understand if subsurface geology has the right structure to store oil and gas<ref>{{Cite journal|last=Lawson|first=M.|date=2018-02-19|title=Geochemical applications in petroleum systems analysis: New constraints and the power of integration|url=https://www.researchgate.net/publication/323282762_Geochemical_applications_in_petroleum_systems_analysis_New_constraints_and_the_power_of_integration|journal=Geological Society, London, Special Publications|volume=468|pages=6}}</ref> . More than locating the reservoir, seismic technology also helps geologists understand its geometry. This includes the shape, thickness, depth and continuity of a reservoir. This matters because a reservoir can be located but not profitable for business. With current technology and the purpose of maximizing the future extraction, geologists are targeting large and continuous reservoirs rather than thin and isolated ones. Seismic data can help pinpoint the drilling target by showing where the reservoir might be thicker or larger<ref name=":0" /> .

An exploration workflow usually starts with a regional study. The first step is for geologists to determine if the region has a petroleum system with possible traps that contain oil. Then there are follow-up seismic surveys to get evidence and more information. Next, geoscientists interpret the data to distinguish geological structures and possible drilling targets. These decisions are assisted by other data, such as core samples. Finally, drilling locations are chosen based on different criteria <ref name=":1">{{Cite journal|last=Ma|first=Yuan Zhe|date=2011-01-01|title=Uncertainty Analysis in Reservoir Characterization and Management: How Much Should We Know About What We Don't Know?|url=https://pubs.geoscienceworld.org/aapg/books/edited-volume/1248/chapter-abstract/107059711/Uncertainty-Analysis-in-Reservoir-Characterization?redirectedFrom=fulltext|journal=AAPG Memoir|volume=1|pages=15}}</ref>.

However, seismic technology is not perfect. As an imaging technique that relies on the reflection of waves, some thin reservoirs or structures can be hard to detect. Also, seismic data cannot directly show the oil and gas but uses structures to infer their existence. Based on this limitation, seismic technology is more like a tool that reduces drilling risk than eliminates all uncertainties <ref>Saad, M. R., & Jadeer, A.-S. (2022). ''Seismic Method for Exploration Oil and Gas Reservoirs''. <nowiki>https://doi.org/10.1007/978-981-99-1964-2_89</nowiki></ref>.

== Oil and Gas Extraction: How Geology Determines Engineering Decisions ==
Once an oil reservoir is proven as continuous and profitable, geology still plays a role in deciding how to extract the resources. In a word, engineering decisions and extraction methods are based on how the subsurface looks and how fluids move through the rock.

Engineers need more geology information before deciding where to drill. They want to know the depth of the potential drilling trajectory, the thickness of the oil reservoir, and the fluid contacts of the reservoir to optimize the performance. For example, a rich oil-bearing zone in the reservoir should be the highest priority to place the well nearby. However, if the zone is disrupted by some faults, then engineers and geologists must determine whether these faults connect to parts of the reservoir or cut it into separate parts. Moreover, if the production well is too close to a water or gas zone, a water or gas breakthrough is likely to happen and reduce oil production. In a real-world case, a breakthrough can easily turn a high-production well into a shut-down.
[[File:Reservori_Simulation_Model.jpg|thumb|Figure 2. The reservoir modeling workflow showing the sequence of stages in data acquisition and interpretation<ref name=":2">Abel, M., Garcia, L., Lorenzatti, A., & De Ros, L. (2010, October 26). ''SEMANTIC INTEROPERABILITY IN THE PETROLEUM CHAIN: THE CONTRIBUTION OF ONTOLOGICAL ANALYSIS''.</ref>|549x549px]]Reservoir simulation is a great tool to use in oil extraction, just like how seismic technology assists oil exploration. A reservoir model is a digital version of a reservoir with a vivid representation of reservoir structures and various relevant properties like pressure, permeability, porosity, and saturation of each phase. Engineers use this model to predict how the reservoir might behave during production. For instance, the model can estimate production rates, pressure changes, and any potential water cut. It can also achieve optimization on certain jobs, like comparing different production plans and well placement strategies. Since the model is built purely based on geological data, its quality varies depending on how well the regional geology is captured and understood, and this can also be a limitation of the reservoir model <ref name=":2" /><ref>Sambo, C., Iferobia, C. C., Babasafari, A. A., Rezaei, S., & Akanni, O. A. (2020). The Role of Time Lapse(4D) Seismic Technology as Reservoir Monitoring and Surveillance Tool: A Comprehensive Review. ''Journal of Natural Gas Science and Engineering'', ''80'', 103312. <nowiki>https://doi.org/10.1016/j.jngse.2020.103312</nowiki></ref>.

Since there are many different types of reservoirs, extraction methods have also been developed differently to achieve efficient production for each case. And they can be separated under two main reservoir types: conventional and unconventional.
{| class="wikitable"
|+
!Reservoir Type
!Geological Characteristics
!Main Extraction Methods
!Engineering
Reason
|-
|Conventional reservoirs
|High permeability and porosity for fluids to flow naturally toward the well through connected pore spaces
|Primary production relies on natural reservoir pressure and secondary recovery methods like water injection are used to maintain the pressure
|Maintain and increase reservoir pressure to improve flow toward production wells
|-
|Unconventional reservoirs
|Low permeability so fluids are trapped in rocks or exist as highly viscous bitumen
|Horizontal drilling and hydraulic fracturing are commonly used for shale gas and tight oil
For deep oil sands, steam-assisted gravity drainage can be used by injecting steam underground to heat bitumen and lower the viscousity
|Create flow pathways to make hydrocarbons mobile enough to be produced
|}
Overall, geology has a strong influence on engineering decisions in oil and gas extraction. Geology informs engineers to know the reservoir quality, what extraction methodology can be applied, and what risks might exist during production. Geological information has also been integrated into reservoir models to provide a more in-depth understanding and optimization. Oil extraction is not just about improving equipment and technology, it is also a process in which geological knowledge is applied with engineering decisions.

== Chemical Engineering and Petroleum Products ==
[[File:Fractional Distillation.jpg|thumb|Fractional Distillation Process of Crude Oil (Wigmore Trading, n.d.)|512x512px]]
Crude oil, in its unrefined state, has almost no direct utility due to its highly complex molecular constitution. It exists fundamentally as a dense, complex mixture of hundreds of different hydrocarbons. The three basic components of crude oil are alkanes, cycloalkanes, and aromatics. The primary steps of chemical engineering within petroleum refineries are physical separation and chemical conversion. The first step separates the heterogeneous mixture into narrower, manageable fractions based on physical properties, and the second step upgrades these fractions into high-value, commercially viable products. This transformation from raw, unusable crude oil into high-value fuels relies on a sequence of thermal processes and complex catalytic reactions that manipulate molecular structures.<ref name=":6">Gary, J.H., Handwerk, J.H., Kaiser, M.J., & Geddes, D. (2007). Petroleum Refining: Technology and Economics, Fifth Edition (5th ed.). CRC Press. <nowiki>https://doi.org/10.4324/9780203907924</nowiki></ref>

The foundational stage of any refinery configuration is fractional distillation. It depends on the differential volatility and boiling points of the constituent hydrocarbons within crude oil. The process is commonly operationalized through the Atmospheric Distillation Unit: crude oil is preheated to approximately 350-400°C and pumped into the lowest and hottest level in the Fractional distillation tower. As the vaporized oil ascends through a series of distillation trays with temperature decreasing, it cools progressively. Hydrocarbons with lower boiling points condense at higher levels of the tower. This allows the continuous withdrawal of light fractions such as liquefied petroleum gas, naphtha, kerosene, and gas oil.<ref name=":6" />

Since the initial fractions obtained from atmospheric distillation are mostly the result of physical separation, they can't break the products into smaller molecules. Those distilled heavy molecules are hardly suitable for the commercial market. Thus, refineries rely heavily on cracking processes to convert these high-molecular-weight hydrocarbons into higher-value, lighter liquid fuels. This process involves the thermal or catalytic breaking of carbon-carbon covalent bonds in long-chain alkanes. Modern chemical engineering uses Fluid Catalytic Cracking (FCC) as the primary process. The market prefers this method due to its ability to maximize high-value gasoline yields from heavy gas oils. The efficiency of FCC is highly influenced by the use of highly active, acidic zeolite catalysts. Zeolite selectively accelerates secondary hydrocarbon cracking while minimizing unwanted coke formation. Alternatively, for middle distillates such as jet fuel and diesel, hydrocracking is used. This process takes place in a high-temperature, high-pressure, hydrogen-rich environment. Over catalysts, the hydrogen saturates aromatic rings and breaks the carbon chains.<ref name=":6" />

Reforming is another chemical process that changes a molecule's structure without altering the overall number of carbon atoms. This method is mainly used for straight-run naphtha, a distillation product. Straight-run naphtha has a suitable molecular size for vehicle engines, but the straight-chain alkanes it contains can cause knocking. Reforming uses chemical reactions to trigger isomerization, cyclization or dehydration of the straight chains. During catalytic reforming, a large amount of hydrogen is formed as a byproduct of dehydrogenation. This is great in the engineering industry, since hydrogen can be pumped straight to hydrotreating. Hydrotreating is a process for purifying. Crude oil naturally contains heteroatom impurities like sulphur, nitrogen, and heavy metals. With the purification process, SOx and NOx won't be released during burning, thereby preventing catalyst poisoning. Under high pressure and temperature, hydrogen can convert sulphur and nitrogen into H2S and NH3, separating the impurities completely.<ref name=":6" />

Through the physical separations and chemical alterations described above, crude oil ultimately becomes market products and plays an important role in the global economy. These outputs are broadly divided into three categories: transportation fuels, industrial specialty products, and petrochemical feedstocks. Transportation fuels such as gasoline, diesel, and kerosene sustain global logistics and transportation networks daily. They determine whether the international trade markets can function efficiently. Industrial specialty products like asphalt, which is extracted from heavy residues, play an indispensable role as the structural binder in global infrastructure development. Nevertheless, according to Levi et al. (2018), straight-run naphtha, serving as a petrochemical feedstock, has been a source for the global chemical industry. Through steam cracking, primary light olefins and aromatics are synthesized. Thus, downstream polymerization can convert them into ubiquitous materials such as polyethylene, polypropylene, and synthetic rubbers.<ref>Levi, P. G., & Cullen, J. M. (2018). Mapping Global Flows of Chemicals: From Fossil Fuel Feedstocks to Chemical Products. ''Environmental science & technology'', ''52''(4), 1725–1734. <nowiki>https://doi.org/10.1021/acs.est.7b04573</nowiki></ref>

== Environmental issues ==
When it comes to gas and oil extraction, environmental concerns are always on the table. Is the project sustainable? Will the extraction cause any irreparable damage to the Earth's environment? Are the operations negatively affecting other living beings' natural habitats? These are all the questions that geologists and engineers constantly ask themselves. To comprehensively assess environmental issues, both onshore and offshore oil and gas developments must be considered.

Onshore operations are raising the risks of induced earthquakes. Engineering techniques used in unconventional reservoirs, such as hydraulic fracturing and wastewater injection, alter subsurface pore-fluid pressure and reduce the shear strength of the original faults. This may increase the possibility of fault slippage, thus triggering seismic events. This phenomenon is particularly frequent in areas with active shale gas extraction. A case study in the Western Canada Sedimentary Basin (WCSB) in northeastern British Columbia, Canada, shows that the high-density hydraulic fracturing and fluid reinjection activities have led to a significant increase in regional background seismicity in recent years. To manage and minimize the damage caused by this issue, both geological and engineering knowledge are required. Since the fault slippage cannot be observed on the surface, a high-precision underground detector must be introduced. The seismic technology used for exploration can now serve as microseismic monitoring networks. Their ability to map subsurface fracture propagation in real time helps detect microseismic events and acoustic emissions. Collaborating with the Traffic Light Protocols (TLPs), which set the seismic magnitude thresholds, operations will be controlled automatically. Once the magnitude reaches a certain level, restrictions such as limiting injection rates or even mandatory shut-in will be imposed immediately.<ref>Pozzobon, C., Liu, Y., Kirkpatrick, J. D., Chesnaux, R., & Kang, M. (2023). Methane emissions from non-producing oil and gas wells and the potential role of seismic activity: A case study in Northeast British Columbia, Canada. Environmental Science & Technology, 57(51), 21673–21680. <nowiki>https://doi.org/10.1021/acs.est.3c06062</nowiki></ref>

The offshore deep-water oil and gas industry faces distinct issues that experts need to address. Exploration seismic technology relies on high-energy acoustic pulses. The noises can travel very far underwater and disrupt the behavioural patterns of some marine mammals that depend heavily on echolocation. The disruption might cause them to show abnormal behaviour, suffer hearing loss, or even get stranded. Spatial and temporal measures must be applied to prevent serious damage to these animals. Governments should establish avoidance rules and marine protected areas to regulate interactions between the extraction team and marine life. Restricted windows must be strictly obeyed during migration and breeding seasons. Minimum buffer zones should be built around sensitive ecological communities to isolate direct physical and acoustic impact.<ref>Cordes, E. E., Jones, D. O. B., Schlacher, T. A., Amon, D. J., Bernardino, A. F., Brooke, S., Carney, R., DeLeo, D. M., et al. (2016). Environmental impacts of the deep-water oil and gas industry: A review to guide management strategies. ''Frontiers in Environmental Science, 4'', Article 58. <nowiki>https://doi.org/10.3389/fenvs.2016.00058</nowiki></ref> Furthermore, the produced water extracted with crude oil is highly toxic and will casue serious environmental consequences if discharged directly into the ocean. It contains a high concentration of salt, toxic dissolved heavy metals and polycyclic aromatic hydrocarbons. Bioaccumulation and chronic toxicity can negatively affect every step of the marine food chain and damage ecosystems. Multi-step purification must be applied using engineering methods such as physical sedimentation, membrane separation, and advanced oxidation. Systematic inspection will ensure compliance with the standards for discharge or reinjection.<ref>Fakhru’l‑Razi, A., Pendashteh, A., Abdullah, L. C., Biak, D. R. A., Madaeni, S. S., & Abidin, Z. Z. (2009). Produced water treatment and reuse: A review. Journal of Hazardous Materials, 170(2–3), 530–551. <nowiki>https://doi.org/10.1016/j.jhazmat.2009.05.044</nowiki></ref>[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Conclusion / Your Evaluation of the Connections==

=== Conclusion: ===

=== Breakdown of group contributions: ===
Marijke:

* Introduction to Petroleum Systems
* Geological Formation
* Reservoir Quality

Jack:

* Oil and Gas Exploration: Seismic Technology
* Oil and Gas Extraction: How Geology Determines Engineering Decisions
Keming:
* Chemical Engineering and Petroleum Products
* Environmental Issues

=== AI Statement: ===
AI tools were used to support brainstorming ideas and to delegate portions within the group. AI-generated images are used and cited. All final written content have been created and reviewed by all group members.

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-18T00:54:29Z

KemingWu: /* Environmental issues */

==Introduction to Petroleum Systems==

Oil and natural gas are among the most important geological resources utilized by modern society. This industry fuels the global economy and energy is used for electricity, transportation, and industrial manufacturing. The oil and gas industry is considered in three main sectors<ref name=":3">{{Cite web|last=McClay|first=R.|date=2025-10-12|title=Understanding the Oil and Gas Industry: A Comprehensive Overview|url=https://www.investopedia.com/investing/oil-gas-industry-overview/|url-status=live|website=Investopedia}}</ref>:
{| class="wikitable"
|'''Upstream Sector'''
|'''Midstream Sector'''
|'''Downstream Sector'''
|-
|Include exploration and production. Companies drill for oil and gas.
|Include transportation and usage. Companies handle transit to oil refineries.
|Include refining and distribution. Companies produce refined oil and gas and sell it as gasoline and jet fuel.
|}
Oil and gas consists of hydrocarbons that form naturally within Earth’s crust over millions of years. Organic material derived from plants, animals, and microbes accumulate within depositions, and over geological time, becomes incorporated into sedimentary rocks. These rocks include sandstone, limestone, and shale, and form in ancient oceans. Burial beneath additional sediment subjects organic matter to high temperatures and pressures, leading to the formation of oil and natural gas within the subsurface<ref name=":3" />.

Hydrocarbons may migrate through porous and permeable sedimentary rocks, as they are less dense than surrounding water. An oil and gas reservoir is created when migrating hydrocarbons reach a barrier. These are the types of reservoirs that are used by the petroleum industry by drilling through overlying rocks into the subsurface reservoir<ref name=":3" />.

The petroleum industry is closely related to chemistry and engineering. Geology identifies the source rocks, reservoirs, seals, and migration pathways required for hydrocarbon accumulation, while chemistry helps explain the transformation into petroleum under changing pressure and temperatures. This directly influences engineering decisions related to exploration, production, and resource development. Petroleum systems demonstrate how geological processes create conditions for both chemical and engineering applications.

== Geological Formation ==
The occurrence of oil and gas within the Earth’s crust is demonstrated by a geological framework known as the Total Petroleum System<ref name=":4">{{Cite journal|last=Magoon|first=L. B.|last2=Schmoker|first2=J. W.|date=2000|title=The Total Petroleum System - The Natural Fluid Network that Constrains the Assessment Unit|url=https://pubs.usgs.gov/dds/dds-060/chaps/PS.pdf|journal=United States Geological Survey|pages=1-20}}</ref>. This is the basis for assessing hydrocarbon resources, as it considers both geological elements and processes required for the accumulations to exist. A petroleum system consists of four essential geological elements; source rock, reservoir rock, seal rock, and overburden rock. The essential processes of the Total Petroleum System are generation, migration, accumulation, and trap formation. The first stage of oil and gas formation is hydrocarbon generation within a source rock, defined as the origin of petroleum within the system. The “pod of active source rock” are adjacent source rocks that are responsible for generating hydrocarbons. Under high temperature and pressure conditions, hydrocarbons are expelled from the source rock and into surrounding rock units<ref name=":4" />.

Once generated, hydrocarbons migrate through the subsurface. A petroleum system requires pathways that allow the oil and gas to move from the source rock and into geological formations that can store hydrocarbons. Without migration pathways, generated hydrocarbons would remain trapped within the source rock and accumulations would not form<ref name=":4" />.
[[File:Figure 1. Geological Cross-Section of an OIl and Gas Reservoir.png|thumb|514x514px|Figure 1. Geological Cross-Section of an Oil and Gas Reservoir]]
Hydrocarbons accumulate within the pores of reservoir rocks. Reservoir rocks are essential to the petroleum system since they provide space for hydrocarbon storage. Reservoir characterization studies evaluate properties including porosity and permeability; qualities that dictate the amount of available hydrocarbon storage as well as the ease that fluid can move within the rock. Reservoir rocks with high porosity and permeability are considered more effective at storing hydrocarbons<ref name=":5" />.

For hydrocarbons to remain within a reservoir, a seal rock must also be present. Seal rocks are identified as one of the four essential petroleum system elements because they act as barriers that restrict fluid movement and prevent hydrocarbons from escaping. Additionally, trap formation must occur to retain migrating hydrocarbons. The process of accumulation and trap formation are together required to create and preserve petroleum deposits<ref name=":4" />.

The final essential element of a petroleum system is overburden rock. Overburden refers to the layers of sediment and rock that accumulate above the source rock and reservoir rock over geological time. As additional sediments are deposited, the increasing thickness of overburden subjects underlying rocks to higher temperatures and processes during burial. These conditions influence the thermal maturity of source rocks and play a crucial role in hydrocarbon generation. Therefore, the thickness and burial history over the overburden can be used by geologists to determine whether or not the source rocks have reached the temperature and pressure conditions that are necessary for oil and gas formation<ref name=":4" />.

== Reservoir Quality ==

The presence of a petroleum system alone does not guarantee that hydrocarbons can be recovered economically. Reservoir quality is primarily determined by porosity and permeability, which are considered the fundamental factors of the petroleum reservoir viability. Porosity is the amount of pore space available within a rock for hydrocarbon storage, while permeability describes the degree to which fluids can move through connected pore networks. Reservoir rocks may contain significant pore space but still be considered poor-quality if pore connections are limited. Consequently, both properties must be evaluated when assessing whether or not a reservoir is considered commercially viable. Other important factors of reservoir quality include depositional environment, sediment provenance, weathering, compaction, dissolution, burial depth, pressure, and structural deformation. Since these controls interact over millions of years, reservoir quality reflects cumulative effects, looking back to initial sediment<ref name=":5" />.

One of the most important controls on reservoir quality is the depositional environment in which the sediment was originally deposited. The primary composition of sediment strongly influences the future evolution of reservoir rocks. In sandstone reservoirs, factors such as the source-area geology, climate, topography, and grain size all affect the resulting rock properties. These factors all influence pore space, and therefore impact reservoir quality. Sediments deposited in shallow marine environments often develop better reservoir properties because they tend to be cleaner and contain fewer fine materials that can reduce pore connections. On the other hand, sediments deposited in low-energy environments may contain more clay and silt, which can negatively affect reservoir quality. Well-sorted sediments generally have more interconnected pores than poorly sorted sediments that contain fine grain matrix material<ref name=":5" />.

Different lithologies also respond differently to geological processes. Sandstone reservoirs are among the most common hydrocarbon reservoirs because they can preserve great porosity between sediment grains. Carbonate reservoirs, including limestone and dolostone, often undergo many diagenetic changes through processes such as dissolution, recrystallization, and dolomitization due to their greater chemical reactivity. Rather than relying solely on primary pore space, carbonate reservoirs often develop secondary porosity through diagenesis and fracturing. As a result, both sandstone and carbonate reservoirs often have the capacity to contain hydrocarbons, although having very different pore systems and geological histories<ref name=":5" />.

Following deposition, sediment undergoes diagenesis when physical and chemical changes occur as the sediment is transformed into sedimentary rock. Important stages in reservoir evolution include eodiagenesis (early burial diagenesis), mesodiagenesis (burial diagenesis), and telodiagenesis (uplift-related changes)<ref name=":5" />. During these stages, sediments experience compaction, dissolution, mineral replacement, fracturing, and fluid interactions that can significantly alter reservoir properties. These diagenetic processes can reduce reservoir quality. Compaction during burial decreases pore space as sediment gains become more tightly packed. Chemical compaction and pressure solution may further reduce porosity. Minerals such as quartz, calcite, dolomite, and clay can fill pore spaces and restrict fluid movement. Quartz cementation is identified as one of the most important pore-filling processes in deep buried sandstone reservoirs because of the way it reduces the amount of available pore space progressively. Clay mineral does so similarly and may significantly decrease permeability by blocking pores and restricting fluid flow <ref name=":5">{{Cite journal|last=Worden|first=R. H.|last2=Armitage|first2=P. J.|last3=Butcher|first3=A. R.|last4=Churchill|first4=J. M.|last5=Csoma|first5=A. E.|last6=Hollis|first6=C.|last7=Lander|first7=R. H.|last8=Omma|first8=J. E.|date=2018|title=Petroleum reservoir quality prediction: overview and contrasting approaches from sandstone and carbonate communities|url=https://doi.org/10.1144/SP435.21|journal=Geological Society|volume=435|pages=1-31}}</ref>.

Reservoir quality is not solely determined by burial and porosity. The final characteristics of a reservoir are reflected by the preservation of pore space. Reservoirs with similar depositional origination may exhibit very different porosity and permeability depending on their diagenetic history and the geological conditions they experienced during burial and uplift<ref name=":5" />.
== Oil and Gas Exploration: Seismic Technology ==

Now we know the importance of oil and gas to our society, and how they were formed, the next question is where to locate them. Since reservoirs are below the surface, geologists cannot directly see where they are before drilling. This makes drilling a gamble, and that's where seismic reflection technology contributes to lowering the risk. It works as a tool that helps geologists to create an image of what is beneath the surface before they decide where to drill <ref name=":0">{{Cite journal|last=Mohammed|first=Farfour|date=2016-05-01|title=A review on multicomponent seismology: A potential seismic application for reservoir characterization|url=https://www.sciencedirect.com/science/article/pii/S2090123215001125|journal=Journal of Advanced Research|volume=3|pages=515-524}}</ref>.[[File:Seismic_Survey_and_Mechanism.png|thumb|left|500x500px|Figure 1. Seismic Technology and Mechanism for oil Exploration]]The working principle behind seismic is to use energy waves to explore underground rock layers. During a survey, energy waves are sent into the ground. When waves hit the boundaries between rock layers, some of the energy bounces back to the surface, while some goes further. Receivers then pick up these reflected waves and give information about the depth, shape and arrangement of subsurface layers by analyzing the different waves using the pre-known typical rock’s density and acoustic impedance. After processing, the data can be shown as profiles or 3D seismic images <ref>{{Cite journal|last=Ilya|first=Tsvankin|date=2010-09-01|title=Seismic anisotropy in exploration and reservoir characterization: An overview|url=https://www.researchgate.net/publication/228633261_Seismic_anisotropy_in_exploration_and_reservoir_characterization_An_overview|journal=Geophysics|volume=75}}</ref>.

This is essential because oil and gas need geological structures to build up, and seismic interpretation helps identify these structures. For example, folds show up as layers in seismic images. If the fold creates an anticline, oil and gas might move upward and get trapped near the top. Faults can be spotted when rock layers are broken or displaced. Faults can create traps but might let hydrocarbons escape as well if they aren't sealed properly. So seismic data are not just used to "find oil", they help us understand if subsurface geology has the right structure to store oil and gas<ref>{{Cite journal|last=Lawson|first=M.|date=2018-02-19|title=Geochemical applications in petroleum systems analysis: New constraints and the power of integration|url=https://www.researchgate.net/publication/323282762_Geochemical_applications_in_petroleum_systems_analysis_New_constraints_and_the_power_of_integration|journal=Geological Society, London, Special Publications|volume=468|pages=6}}</ref> . More than locating the reservoir, seismic technology also helps geologists understand its geometry. This includes the shape, thickness, depth and continuity of a reservoir. This matters because a reservoir can be located but not profitable for business. With current technology and the purpose of maximizing the future extraction, geologists are targeting large and continuous reservoirs rather than thin and isolated ones. Seismic data can help pinpoint the drilling target by showing where the reservoir might be thicker or larger<ref name=":0" /> .

An exploration workflow usually starts with a regional study. The first step is for geologists to determine if the region has a petroleum system with possible traps that contain oil. Then there are follow-up seismic surveys to get evidence and more information. Next, geoscientists interpret the data to distinguish geological structures and possible drilling targets. These decisions are assisted by other data, such as core samples. Finally, drilling locations are chosen based on different criteria <ref name=":1">{{Cite journal|last=Ma|first=Yuan Zhe|date=2011-01-01|title=Uncertainty Analysis in Reservoir Characterization and Management: How Much Should We Know About What We Don't Know?|url=https://pubs.geoscienceworld.org/aapg/books/edited-volume/1248/chapter-abstract/107059711/Uncertainty-Analysis-in-Reservoir-Characterization?redirectedFrom=fulltext|journal=AAPG Memoir|volume=1|pages=15}}</ref>.

However, seismic technology is not perfect. As an imaging technique that relies on the reflection of waves, some thin reservoirs or structures can be hard to detect. Also, seismic data cannot directly show the oil and gas but uses structures to infer their existence. Based on this limitation, seismic technology is more like a tool that reduces drilling risk than eliminates all uncertainties <ref>Saad, M. R., & Jadeer, A.-S. (2022). ''Seismic Method for Exploration Oil and Gas Reservoirs''. <nowiki>https://doi.org/10.1007/978-981-99-1964-2_89</nowiki></ref>.

== Oil and Gas Extraction: How Geology Determines Engineering Decisions ==
Once an oil reservoir is proven as continuous and profitable, geology still plays a role in deciding how to extract the resources. In a word, engineering decisions and extraction methods are based on how the subsurface looks and how fluids move through the rock.

Engineers need more geology information before deciding where to drill. They want to know the depth of the potential drilling trajectory, the thickness of the oil reservoir, and the fluid contacts of the reservoir to optimize the performance. For example, a rich oil-bearing zone in the reservoir should be the highest priority to place the well nearby. However, if the zone is disrupted by some faults, then engineers and geologists must determine whether these faults connect to parts of the reservoir or cut it into separate parts. Moreover, if the production well is too close to a water or gas zone, a water or gas breakthrough is likely to happen and reduce oil production. In a real-world case, a breakthrough can easily turn a high-production well into a shut-down.
[[File:Reservori_Simulation_Model.jpg|thumb|Figure 2. The reservoir modeling workflow showing the sequence of stages in data acquisition and interpretation<ref name=":2">Abel, M., Garcia, L., Lorenzatti, A., & De Ros, L. (2010, October 26). ''SEMANTIC INTEROPERABILITY IN THE PETROLEUM CHAIN: THE CONTRIBUTION OF ONTOLOGICAL ANALYSIS''.</ref>|549x549px]]Reservoir simulation is a great tool to use in oil extraction, just like how seismic technology assists oil exploration. A reservoir model is a digital version of a reservoir with a vivid representation of reservoir structures and various relevant properties like pressure, permeability, porosity, and saturation of each phase. Engineers use this model to predict how the reservoir might behave during production. For instance, the model can estimate production rates, pressure changes, and any potential water cut. It can also achieve optimization on certain jobs, like comparing different production plans and well placement strategies. Since the model is built purely based on geological data, its quality varies depending on how well the regional geology is captured and understood, and this can also be a limitation of the reservoir model <ref name=":2" /><ref>Sambo, C., Iferobia, C. C., Babasafari, A. A., Rezaei, S., & Akanni, O. A. (2020). The Role of Time Lapse(4D) Seismic Technology as Reservoir Monitoring and Surveillance Tool: A Comprehensive Review. ''Journal of Natural Gas Science and Engineering'', ''80'', 103312. <nowiki>https://doi.org/10.1016/j.jngse.2020.103312</nowiki></ref>.

Since there are many different types of reservoirs, extraction methods have also been developed differently to achieve efficient production for each case. And they can be separated under two main reservoir types: conventional and unconventional.
{| class="wikitable"
|+
!Reservoir Type
!Geological Characteristics
!Main Extraction Methods
!Engineering
Reason
|-
|Conventional reservoirs
|High permeability and porosity for fluids to flow naturally toward the well through connected pore spaces
|Primary production relies on natural reservoir pressure and secondary recovery methods like water injection are used to maintain the pressure
|Maintain and increase reservoir pressure to improve flow toward production wells
|-
|Unconventional reservoirs
|Low permeability so fluids are trapped in rocks or exist as highly viscous bitumen
|Horizontal drilling and hydraulic fracturing are commonly used for shale gas and tight oil
For deep oil sands, steam-assisted gravity drainage can be used by injecting steam underground to heat bitumen and lower the viscousity
|Create flow pathways to make hydrocarbons mobile enough to be produced
|}
Overall, geology has a strong influence on engineering decisions in oil and gas extraction. Geology informs engineers to know the reservoir quality, what extraction methodology can be applied, and what risks might exist during production. Geological information has also been integrated into reservoir models to provide a more in-depth understanding and optimization. Oil extraction is not just about improving equipment and technology, it is also a process in which geological knowledge is applied with engineering decisions.

== Chemical Engineering and Petroleum Products ==
[[File:Fractional Distillation.jpg|thumb|Fractional Distillation Process of Crude Oil (Wigmore Trading, n.d.)|512x512px]]
Crude oil, in its unrefined state, has almost no direct utility due to its highly complex molecular constitution. It exists fundamentally as a dense, complex mixture of hundreds of different hydrocarbons. The three basic components of crude oil are alkanes, cycloalkanes, and aromatics. The primary steps of chemical engineering within petroleum refineries are physical separation and chemical conversion. The first step separates the heterogeneous mixture into narrower, manageable fractions based on physical properties, and the second step upgrades these fractions into high-value, commercially viable products. This transformation from raw, unusable crude oil into high-value fuels relies on a sequence of thermal processes and complex catalytic reactions that manipulate molecular structures. (Sani et al., 2024)

The foundational stage of any refinery configuration is fractional distillation. It depends on the differential volatility and boiling points of the constituent hydrocarbons within crude oil. The process is commonly operationalized through the Atmospheric Distillation Unit: crude oil is preheated to approximately 350-400°C and pumped into the lowest and hottest level in the Fractional distillation tower. As the vaporized oil ascends through a series of distillation trays with temperature decreasing, it cools progressively. Hydrocarbons with lower boiling points condense at higher levels of the tower. This allows the continuous withdrawal of light fractions such as liquefied petroleum gas, naphtha, kerosene, and gas oil. (Sani et al., 2024)

Since the initial fractions obtained from atmospheric distillation are mostly the result of physical separation, they can't break the products into smaller molecules. Those distilled heavy molecules are hardly suitable for the commercial market. Thus, refineries rely heavily on cracking processes to convert these high-molecular-weight hydrocarbons into higher-value, lighter liquid fuels. This process involves the thermal or catalytic breaking of carbon-carbon covalent bonds in long-chain alkanes. Modern chemical engineering uses Fluid Catalytic Cracking (FCC) as the primary process. The market prefers this method due to its ability to maximize high-value gasoline yields from heavy gas oils. The efficiency of FCC is highly influenced by the use of highly active, acidic zeolite catalysts. Zeolite selectively accelerates secondary hydrocarbon cracking while minimizing unwanted coke formation. Alternatively, for middle distillates such as jet fuel and diesel, hydrocracking is used. This process takes place in a high-temperature, high-pressure, hydrogen-rich environment. Over catalysts, the hydrogen saturates aromatic rings and breaks the carbon chains. (Sani et al., 2024)

Reforming is another chemical process that changes a molecule's structure without altering the overall number of carbon atoms. This method is mainly used for straight-run naphtha, a distillation product. Straight-run naphtha has a suitable molecular size for vehicle engines, but the straight-chain alkanes it contains can cause knocking. Reforming uses chemical reactions to trigger isomerization, cyclization or dehydration of the straight chains. During catalytic reforming, a large amount of hydrogen is formed as a byproduct of dehydrogenation. This is great in the engineering industry, since hydrogen can be pumped straight to hydrotreating. Hydrotreating is a process for purifying. Crude oil naturally contains heteroatom impurities like sulphur, nitrogen, and heavy metals. With the purification process, SOx and NOx won't be released during burning, thereby preventing catalyst poisoning. Under high pressure and temperature, hydrogen can convert sulphur and nitrogen into H2S and NH3, separating the impurities completely. (Sani et al., 2024)

Through the physical separations and chemical alterations described above, crude oil ultimately becomes market products and plays an important role in the global economy. These outputs are broadly divided into three categories: transportation fuels, industrial specialty products, and petrochemical feedstocks. Transportation fuels such as gasoline, diesel, and kerosene sustain global logistics and transportation networks daily. They determine whether the international trade markets can function efficiently. Industrial specialty products like asphalt, which is extracted from heavy residues, play an indispensable role as the structural binder in global infrastructure development. Nevertheless, according to Levi et al. (2018), straight-run naphtha, serving as a petrochemical feedstock, has been a source for the global chemical industry. Through steam cracking, primary light olefins and aromatics are synthesized. Thus, downstream polymerization can convert them into ubiquitous materials such as polyethylene, polypropylene, and synthetic rubbers. (Levi et al., 2018)

== Environmental issues ==
When it comes to gas and oil extraction, environmental concerns are always on the table. Is the project sustainable? Will the extraction cause any irreparable damage to the Earth's environment? Are the operations negatively affecting other living beings' natural habitats? These are all the questions that geologists and engineers constantly ask themselves. To comprehensively assess environmental issues, both onshore and offshore oil and gas developments must be considered.

Onshore operations are raising the risks of induced earthquakes. Engineering techniques used in unconventional reservoirs, such as hydraulic fracturing and wastewater injection, alter subsurface pore-fluid pressure and reduce the shear strength of the original faults. This may increase the possibility of fault slippage, thus triggering seismic events. This phenomenon is particularly frequent in areas with active shale gas extraction. A case study in the Western Canada Sedimentary Basin (WCSB) in northeastern British Columbia, Canada, shows that the high-density hydraulic fracturing and fluid reinjection activities have led to a significant increase in regional background seismicity in recent years. To manage and minimize the damage caused by this issue, both geological and engineering knowledge are required. Since the fault slippage cannot be observed on the surface, a high-precision underground detector must be introduced. The seismic technology used for exploration can now serve as microseismic monitoring networks. Their ability to map subsurface fracture propagation in real time helps detect microseismic events and acoustic emissions. Collaborating with the Traffic Light Protocols (TLPs), which set the seismic magnitude thresholds, operations will be controlled automatically. Once the magnitude reaches a certain level, restrictions such as limiting injection rates or even mandatory shut-in will be imposed immediately. (Pozzobon et al., 2023)

The offshore deep-water oil and gas industry faces distinct issues that experts need to address. Exploration seismic technology relies on high-energy acoustic pulses. The noises can travel very far underwater and disrupt the behavioural patterns of some marine mammals that depend heavily on echolocation. The disruption might cause them to show abnormal behaviour, suffer hearing loss, or even get stranded. Spatial and temporal measures must be applied to prevent serious damage to these animals. Governments should establish avoidance rules and marine protected areas to regulate interactions between the extraction team and marine life. Restricted windows must be strictly obeyed during migration and breeding seasons. Minimum buffer zones should be built around sensitive ecological communities to isolate direct physical and acoustic impact. (Cordes et al., 2016) Furthermore, the produced water extracted with crude oil is highly toxic and will casue serious environmental consequences if discharged directly into the ocean. It contains a high concentration of salt, toxic dissolved heavy metals and polycyclic aromatic hydrocarbons. Bioaccumulation and chronic toxicity can negatively affect every step of the marine food chain and damage ecosystems. Multi-step purification must be applied using engineering methods such as physical sedimentation, membrane separation, and advanced oxidation. Systematic inspection will ensure compliance with the standards for discharge or reinjection. (Fakhru’l-Razi et al., 2009)[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Conclusion / Your Evaluation of the Connections==

=== Conclusion: ===

=== Breakdown of group contributions: ===
Marijke:

* Introduction to Petroleum Systems
* Geological Formation
* Reservoir Quality

Jack:

* Oil and Gas Exploration: Seismic Technology
* Oil and Gas Extraction: How Geology Determines Engineering Decisions
Keming:
* Chemical Engineering and Petroleum Products
* Environmental Issues

=== AI Statement: ===
AI tools were used to support brainstorming ideas and to delegate portions within the group. AI-generated images are used and cited. All final written content have been created and reviewed by all group members.

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-18T00:03:11Z

KemingWu: /* Environmental issues */

==Introduction to Petroleum Systems==

Oil and natural gas are among the most important geological resources utilized by modern society. This industry fuels the global economy and energy is used for electricity, transportation, and industrial manufacturing. The oil and gas industry is considered in three main sectors<ref name=":3">{{Cite web|last=McClay|first=R.|date=2025-10-12|title=Understanding the Oil and Gas Industry: A Comprehensive Overview|url=https://www.investopedia.com/investing/oil-gas-industry-overview/|url-status=live|website=Investopedia}}</ref>:
{| class="wikitable"
|'''Upstream Sector'''
|'''Midstream Sector'''
|'''Downstream Sector'''
|-
|Include exploration and production. Companies drill for oil and gas.
|Include transportation and usage. Companies handle transit to oil refineries.
|Include refining and distribution. Companies produce refined oil and gas and sell it as gasoline and jet fuel.
|}
Oil and gas consists of hydrocarbons that form naturally within Earth’s crust over millions of years. Organic material derived from plants, animals, and microbes accumulate within depositions, and over geological time, becomes incorporated into sedimentary rocks. These rocks include sandstone, limestone, and shale, and form in ancient oceans. Burial beneath additional sediment subjects organic matter to high temperatures and pressures, leading to the formation of oil and natural gas within the subsurface<ref name=":3" />.

Hydrocarbons may migrate through porous and permeable sedimentary rocks, as they are less dense than surrounding water. An oil and gas reservoir is created when migrating hydrocarbons reach a barrier. These are the types of reservoirs that are used by the petroleum industry by drilling through overlying rocks into the subsurface reservoir<ref name=":3" />.

The petroleum industry is closely related to chemistry and engineering. Geology identifies the source rocks, reservoirs, seals, and migration pathways required for hydrocarbon accumulation, while chemistry helps explain the transformation into petroleum under changing pressure and temperatures. This directly influences engineering decisions related to exploration, production, and resource development. Petroleum systems demonstrate how geological processes create conditions for both chemical and engineering applications.

== Geological Formation ==
The occurrence of oil and gas within the Earth’s crust is demonstrated by a geological framework known as the Total Petroleum System<ref name=":4">{{Cite journal|last=Magoon|first=L. B.|last2=Schmoker|first2=J. W.|date=2000|title=The Total Petroleum System - The Natural Fluid Network that Constrains the Assessment Unit|url=https://pubs.usgs.gov/dds/dds-060/chaps/PS.pdf|journal=United States Geological Survey|pages=1-20}}</ref>. This is the basis for assessing hydrocarbon resources, as it considers both geological elements and processes required for the accumulations to exist. A petroleum system consists of four essential geological elements; source rock, reservoir rock, seal rock, and overburden rock. The essential processes of the Total Petroleum System are generation, migration, accumulation, and trap formation. The first stage of oil and gas formation is hydrocarbon generation within a source rock, defined as the origin of petroleum within the system. The “pod of active source rock” are adjacent source rocks that are responsible for generating hydrocarbons. Under high temperature and pressure conditions, hydrocarbons are expelled from the source rock and into surrounding rock units<ref name=":4" />.

Once generated, hydrocarbons migrate through the subsurface. A petroleum system requires pathways that allow the oil and gas to move from the source rock and into geological formations that can store hydrocarbons. Without migration pathways, generated hydrocarbons would remain trapped within the source rock and accumulations would not form<ref name=":4" />.
[[File:Figure 1. Geological Cross-Section of an OIl and Gas Reservoir.png|thumb|514x514px|Figure 1. Geological Cross-Section of an Oil and Gas Reservoir]]
Hydrocarbons accumulate within the pores of reservoir rocks. Reservoir rocks are essential to the petroleum system since they provide space for hydrocarbon storage. Reservoir characterization studies evaluate properties including porosity and permeability; qualities that dictate the amount of available hydrocarbon storage as well as the ease that fluid can move within the rock. Reservoir rocks with high porosity and permeability are considered more effective at storing hydrocarbons<ref name=":5" />.

For hydrocarbons to remain within a reservoir, a seal rock must also be present. Seal rocks are identified as one of the four essential petroleum system elements because they act as barriers that restrict fluid movement and prevent hydrocarbons from escaping. Additionally, trap formation must occur to retain migrating hydrocarbons. The process of accumulation and trap formation are together required to create and preserve petroleum deposits<ref name=":4" />.

The final essential element of a petroleum system is overburden rock. Overburden refers to the layers of sediment and rock that accumulate above the source rock and reservoir rock over geological time. As additional sediments are deposited, the increasing thickness of overburden subjects underlying rocks to higher temperatures and processes during burial. These conditions influence the thermal maturity of source rocks and play a crucial role in hydrocarbon generation. Therefore, the thickness and burial history over the overburden can be used by geologists to determine whether or not the source rocks have reached the temperature and pressure conditions that are necessary for oil and gas formation<ref name=":4" />.

== Reservoir Quality ==

The presence of a petroleum system alone does not guarantee that hydrocarbons can be recovered economically. Reservoir quality is primarily determined by porosity and permeability, which are considered the fundamental factors of the petroleum reservoir viability. Porosity is the amount of pore space available within a rock for hydrocarbon storage, while permeability describes the degree to which fluids can move through connected pore networks. Reservoir rocks may contain significant pore space but still be considered poor-quality if pore connections are limited. Consequently, both properties must be evaluated when assessing whether or not a reservoir is considered commercially viable. Other important factors of reservoir quality include depositional environment, sediment provenance, weathering, compaction, dissolution, burial depth, pressure, and structural deformation. Since these controls interact over millions of years, reservoir quality reflects cumulative effects, looking back to initial sediment<ref name=":5" />.

One of the most important controls on reservoir quality is the depositional environment in which the sediment was originally deposited. The primary composition of sediment strongly influences the future evolution of reservoir rocks. In sandstone reservoirs, factors such as the source-area geology, climate, topography, and grain size all affect the resulting rock properties. These factors all influence pore space, and therefore impact reservoir quality. Sediments deposited in shallow marine environments often develop better reservoir properties because they tend to be cleaner and contain fewer fine materials that can reduce pore connections. On the other hand, sediments deposited in low-energy environments may contain more clay and silt, which can negatively affect reservoir quality. Well-sorted sediments generally have more interconnected pores than poorly sorted sediments that contain fine grain matrix material<ref name=":5" />.

Different lithologies also respond differently to geological processes. Sandstone reservoirs are among the most common hydrocarbon reservoirs because they can preserve great porosity between sediment grains. Carbonate reservoirs, including limestone and dolostone, often undergo many diagenetic changes through processes such as dissolution, recrystallization, and dolomitization due to their greater chemical reactivity. Rather than relying solely on primary pore space, carbonate reservoirs often develop secondary porosity through diagenesis and fracturing. As a result, both sandstone and carbonate reservoirs often have the capacity to contain hydrocarbons, although having very different pore systems and geological histories<ref name=":5" />.

Following deposition, sediment undergoes diagenesis when physical and chemical changes occur as the sediment is transformed into sedimentary rock. Important stages in reservoir evolution include eodiagenesis (early burial diagenesis), mesodiagenesis (burial diagenesis), and telodiagenesis (uplift-related changes)<ref name=":5" />. During these stages, sediments experience compaction, dissolution, mineral replacement, fracturing, and fluid interactions that can significantly alter reservoir properties. These diagenetic processes can reduce reservoir quality. Compaction during burial decreases pore space as sediment gains become more tightly packed. Chemical compaction and pressure solution may further reduce porosity. Minerals such as quartz, calcite, dolomite, and clay can fill pore spaces and restrict fluid movement. Quartz cementation is identified as one of the most important pore-filling processes in deep buried sandstone reservoirs because of the way it reduces the amount of available pore space progressively. Clay mineral does so similarly and may significantly decrease permeability by blocking pores and restricting fluid flow <ref name=":5">{{Cite journal|last=Worden|first=R. H.|last2=Armitage|first2=P. J.|last3=Butcher|first3=A. R.|last4=Churchill|first4=J. M.|last5=Csoma|first5=A. E.|last6=Hollis|first6=C.|last7=Lander|first7=R. H.|last8=Omma|first8=J. E.|date=2018|title=Petroleum reservoir quality prediction: overview and contrasting approaches from sandstone and carbonate communities|url=https://doi.org/10.1144/SP435.21|journal=Geological Society|volume=435|pages=1-31}}</ref>.

Reservoir quality is not solely determined by burial and porosity. The final characteristics of a reservoir are reflected by the preservation of pore space. Reservoirs with similar depositional origination may exhibit very different porosity and permeability depending on their diagenetic history and the geological conditions they experienced during burial and uplift<ref name=":5" />.
== Oil and Gas Exploration: Seismic Technology ==

Now we know the importance of oil and gas to our society, and how they were formed, the next question is where to locate them. Since reservoirs are below the surface, geologists cannot directly see where they are before drilling. This makes drilling a gamble, and that's where seismic reflection technology contributes to lowering the risk. It works as a tool that helps geologists to create an image of what is beneath the surface before they decide where to drill <ref name=":0">{{Cite journal|last=Mohammed|first=Farfour|date=2016-05-01|title=A review on multicomponent seismology: A potential seismic application for reservoir characterization|url=https://www.sciencedirect.com/science/article/pii/S2090123215001125|journal=Journal of Advanced Research|volume=3|pages=515-524}}</ref>.[[File:Seismic_Survey_and_Mechanism.png|thumb|left|500x500px|Figure 1. Seismic Technology and Mechanism for oil Exploration]]The working principle behind seismic is to use energy waves to explore underground rock layers. During a survey, energy waves are sent into the ground. When waves hit the boundaries between rock layers, some of the energy bounces back to the surface, while some goes further. Receivers then pick up these reflected waves and give information about the depth, shape and arrangement of subsurface layers by analyzing the different waves using the pre-known typical rock’s density and acoustic impedance. After processing, the data can be shown as profiles or 3D seismic images <ref>{{Cite journal|last=Ilya|first=Tsvankin|date=2010-09-01|title=Seismic anisotropy in exploration and reservoir characterization: An overview|url=https://www.researchgate.net/publication/228633261_Seismic_anisotropy_in_exploration_and_reservoir_characterization_An_overview|journal=Geophysics|volume=75}}</ref>.

This is essential because oil and gas need geological structures to build up, and seismic interpretation helps identify these structures. For example, folds show up as layers in seismic images. If the fold creates an anticline, oil and gas might move upward and get trapped near the top. Faults can be spotted when rock layers are broken or displaced. Faults can create traps but might let hydrocarbons escape as well if they aren't sealed properly. So seismic data are not just used to "find oil", they help us understand if subsurface geology has the right structure to store oil and gas<ref>{{Cite journal|last=Lawson|first=M.|date=2018-02-19|title=Geochemical applications in petroleum systems analysis: New constraints and the power of integration|url=https://www.researchgate.net/publication/323282762_Geochemical_applications_in_petroleum_systems_analysis_New_constraints_and_the_power_of_integration|journal=Geological Society, London, Special Publications|volume=468|pages=6}}</ref> . More than locating the reservoir, seismic technology also helps geologists understand its geometry. This includes the shape, thickness, depth and continuity of a reservoir. This matters because a reservoir can be located but not profitable for business. With current technology and the purpose of maximizing the future extraction, geologists are targeting large and continuous reservoirs rather than thin and isolated ones. Seismic data can help pinpoint the drilling target by showing where the reservoir might be thicker or larger<ref name=":0" /> .

An exploration workflow usually starts with a regional study. The first step is for geologists to determine if the region has a petroleum system with possible traps that contain oil. Then there are follow-up seismic surveys to get evidence and more information. Next, geoscientists interpret the data to distinguish geological structures and possible drilling targets. These decisions are assisted by other data, such as core samples. Finally, drilling locations are chosen based on different criteria <ref name=":1">{{Cite journal|last=Ma|first=Yuan Zhe|date=2011-01-01|title=Uncertainty Analysis in Reservoir Characterization and Management: How Much Should We Know About What We Don't Know?|url=https://pubs.geoscienceworld.org/aapg/books/edited-volume/1248/chapter-abstract/107059711/Uncertainty-Analysis-in-Reservoir-Characterization?redirectedFrom=fulltext|journal=AAPG Memoir|volume=1|pages=15}}</ref>.

However, seismic technology is not perfect. As an imaging technique that relies on the reflection of waves, some thin reservoirs or structures can be hard to detect. Also, seismic data cannot directly show the oil and gas but uses structures to infer their existence. Based on this limitation, seismic technology is more like a tool that reduces drilling risk than eliminates all uncertainties <ref>Saad, M. R., & Jadeer, A.-S. (2022). ''Seismic Method for Exploration Oil and Gas Reservoirs''. <nowiki>https://doi.org/10.1007/978-981-99-1964-2_89</nowiki></ref>.

== Oil and Gas Extraction: How Geology Determines Engineering Decisions ==
Once an oil reservoir is proven as continuous and profitable, geology still plays a role in deciding how to extract the resources. In a word, engineering decisions and extraction methods are based on how the subsurface looks and how fluids move through the rock.

Engineers need more geology information before deciding where to drill. They want to know the depth of the potential drilling trajectory, the thickness of the oil reservoir, and the fluid contacts of the reservoir to optimize the performance. For example, a rich oil-bearing zone in the reservoir should be the highest priority to place the well nearby. However, if the zone is disrupted by some faults, then engineers and geologists must determine whether these faults connect to parts of the reservoir or cut it into separate parts. Moreover, if the production well is too close to a water or gas zone, a water or gas breakthrough is likely to happen and reduce oil production. In a real-world case, a breakthrough can easily turn a high-production well into a shut-down.
[[File:Reservori_Simulation_Model.jpg|thumb|Figure 2. The reservoir modeling workflow showing the sequence of stages in data acquisition and interpretation<ref name=":2">Abel, M., Garcia, L., Lorenzatti, A., & De Ros, L. (2010, October 26). ''SEMANTIC INTEROPERABILITY IN THE PETROLEUM CHAIN: THE CONTRIBUTION OF ONTOLOGICAL ANALYSIS''.</ref>|549x549px]]Reservoir simulation is a great tool to use in oil extraction, just like how seismic technology assists oil exploration. A reservoir model is a digital version of a reservoir with a vivid representation of reservoir structures and various relevant properties like pressure, permeability, porosity, and saturation of each phase. Engineers use this model to predict how the reservoir might behave during production. For instance, the model can estimate production rates, pressure changes, and any potential water cut. It can also achieve optimization on certain jobs, like comparing different production plans and well placement strategies. Since the model is built purely based on geological data, its quality varies depending on how well the regional geology is captured and understood, and this can also be a limitation of the reservoir model <ref name=":2" /><ref>Sambo, C., Iferobia, C. C., Babasafari, A. A., Rezaei, S., & Akanni, O. A. (2020). The Role of Time Lapse(4D) Seismic Technology as Reservoir Monitoring and Surveillance Tool: A Comprehensive Review. ''Journal of Natural Gas Science and Engineering'', ''80'', 103312. <nowiki>https://doi.org/10.1016/j.jngse.2020.103312</nowiki></ref>.

Since there are many different types of reservoirs, extraction methods have also been developed differently to achieve efficient production for each case. And they can be separated under two main reservoir types: conventional and unconventional.
{| class="wikitable"
|+
!Reservoir Type
!Geological Characteristics
!Main Extraction Methods
!Engineering
Reason
|-
|Conventional reservoirs
|High permeability and porosity for fluids to flow naturally toward the well through connected pore spaces
|Primary production relies on natural reservoir pressure and secondary recovery methods like water injection are used to maintain the pressure
|Maintain and increase reservoir pressure to improve flow toward production wells
|-
|Unconventional reservoirs
|Low permeability so fluids are trapped in rocks or exist as highly viscous bitumen
|Horizontal drilling and hydraulic fracturing are commonly used for shale gas and tight oil
For deep oil sands, steam-assisted gravity drainage can be used by injecting steam underground to heat bitumen and lower the viscousity
|Create flow pathways to make hydrocarbons mobile enough to be produced
|}
Overall, geology has a strong influence on engineering decisions in oil and gas extraction. Geology informs engineers to know the reservoir quality, what extraction methodology can be applied, and what risks might exist during production. Geological information has also been integrated into reservoir models to provide a more in-depth understanding and optimization. Oil extraction is not just about improving equipment and technology, it is also a process in which geological knowledge is applied with engineering decisions.

== Chemical Engineering and Petroleum Products ==
[[File:Fractional Distillation.jpg|thumb|Fractional Distillation Process of Crude Oil (Wigmore Trading, n.d.)|512x512px]]
Crude oil, in its unrefined state, has almost no direct utility due to its highly complex molecular constitution. It exists fundamentally as a dense, complex mixture of hundreds of different hydrocarbons. The three basic components of crude oil are alkanes, cycloalkanes, and aromatics. The primary steps of chemical engineering within petroleum refineries are physical separation and chemical conversion. The first step separates the heterogeneous mixture into narrower, manageable fractions based on physical properties, and the second step upgrades these fractions into high-value, commercially viable products. This transformation from raw, unusable crude oil into high-value fuels relies on a sequence of thermal processes and complex catalytic reactions that manipulate molecular structures. (Sani et al., 2024)

The foundational stage of any refinery configuration is fractional distillation. It depends on the differential volatility and boiling points of the constituent hydrocarbons within crude oil. The process is commonly operationalized through the Atmospheric Distillation Unit: crude oil is preheated to approximately 350-400°C and pumped into the lowest and hottest level in the Fractional distillation tower. As the vaporized oil ascends through a series of distillation trays with temperature decreasing, it cools progressively. Hydrocarbons with lower boiling points condense at higher levels of the tower. This allows the continuous withdrawal of light fractions such as liquefied petroleum gas, naphtha, kerosene, and gas oil. (Sani et al., 2024)

Since the initial fractions obtained from atmospheric distillation are mostly the result of physical separation, they can't break the products into smaller molecules. Those distilled heavy molecules are hardly suitable for the commercial market. Thus, refineries rely heavily on cracking processes to convert these high-molecular-weight hydrocarbons into higher-value, lighter liquid fuels. This process involves the thermal or catalytic breaking of carbon-carbon covalent bonds in long-chain alkanes. Modern chemical engineering uses Fluid Catalytic Cracking (FCC) as the primary process. The market prefers this method due to its ability to maximize high-value gasoline yields from heavy gas oils. The efficiency of FCC is highly influenced by the use of highly active, acidic zeolite catalysts. Zeolite selectively accelerates secondary hydrocarbon cracking while minimizing unwanted coke formation. Alternatively, for middle distillates such as jet fuel and diesel, hydrocracking is used. This process takes place in a high-temperature, high-pressure, hydrogen-rich environment. Over catalysts, the hydrogen saturates aromatic rings and breaks the carbon chains. (Sani et al., 2024)

Reforming is another chemical process that changes a molecule's structure without altering the overall number of carbon atoms. This method is mainly used for straight-run naphtha, a distillation product. Straight-run naphtha has a suitable molecular size for vehicle engines, but the straight-chain alkanes it contains can cause knocking. Reforming uses chemical reactions to trigger isomerization, cyclization or dehydration of the straight chains. During catalytic reforming, a large amount of hydrogen is formed as a byproduct of dehydrogenation. This is great in the engineering industry, since hydrogen can be pumped straight to hydrotreating. Hydrotreating is a process for purifying. Crude oil naturally contains heteroatom impurities like sulphur, nitrogen, and heavy metals. With the purification process, SOx and NOx won't be released during burning, thereby preventing catalyst poisoning. Under high pressure and temperature, hydrogen can convert sulphur and nitrogen into H2S and NH3, separating the impurities completely. (Sani et al., 2024)

Through the physical separations and chemical alterations described above, crude oil ultimately becomes market products and plays an important role in the global economy. These outputs are broadly divided into three categories: transportation fuels, industrial specialty products, and petrochemical feedstocks. Transportation fuels such as gasoline, diesel, and kerosene sustain global logistics and transportation networks daily. They determine whether the international trade markets can function efficiently. Industrial specialty products like asphalt, which is extracted from heavy residues, play an indispensable role as the structural binder in global infrastructure development. Nevertheless, according to Levi et al. (2018), straight-run naphtha, serving as a petrochemical feedstock, has been a source for the global chemical industry. Through steam cracking, primary light olefins and aromatics are synthesized. Thus, downstream polymerization can convert them into ubiquitous materials such as polyethylene, polypropylene, and synthetic rubbers. (Levi et al., 2018)

== Environmental issues ==
When it comes to gas and oil extraction, environmental concerns are always on the table. Is the project sustainable? Will the extraction cause any irreparable damage to the Earth's environment? Are the operations negatively affecting other living beings' natural habitats? These are all the questions that geologists and engineers constantly ask themselves. To comprehensively assess environmental issues, both onshore and offshore oil and gas developments must be considered.

Onshore operations are raising the risks of induced earthquakes. Engineering techniques used in unconventional reservoirs, such as hydraulic fracturing and wastewater injection, alter subsurface pore-fluid pressure and reduce the shear strength of the original faults. This may increase the possibility of fault slippage, thus triggering seismic events. This phenomenon is particularly frequent in areas with active shale gas extraction. A case study in the Western Canada Sedimentary Basin (WCSB) in northeastern British Columbia, Canada, shows that the high-density hydraulic fracturing and fluid reinjection activities have led to a significant increase in regional background seismicity in recent years. To manage and minimize the damage caused by this issue, both geological and engineering knowledge are required. Since the fault slippage cannot be observed on the surface, a high-precision underground detector must be introduced. The seismic technology used for exploration can now serve as microseismic monitoring networks. Their ability to map subsurface fracture propagation in real time helps detect microseismic events and acoustic emissions. Collaborating with the Traffic Light Protocols (TLPs), which set the seismic magnitude thresholds, operations will be controlled automatically. Once the magnitude reaches a certain level, restrictions such as limiting injection rates or even mandatory shut-in will be imposed immediately. (Pozzobon et al., 2023)[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Conclusion / Your Evaluation of the Connections==

=== Conclusion: ===

=== Breakdown of group contributions: ===
Marijke:

* Introduction to Petroleum Systems
* Geological Formation
* Reservoir Quality

Jack:

* Oil and Gas Exploration: Seismic Technology
* Oil and Gas Extraction: How Geology Determines Engineering Decisions
Keming:
* Chemical Engineering and Petroleum Products
* Environmental Issues

=== AI Statement: ===
AI tools were used to support brainstorming ideas and to delegate portions within the group. AI-generated images are used and cited. All final written content have been created and reviewed by all group members.

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-17T23:39:34Z

KemingWu: /* Environmental issues */

==Introduction to Petroleum Systems==

Oil and natural gas are among the most important geological resources utilized by modern society. This industry fuels the global economy and energy is used for electricity, transportation, and industrial manufacturing. The oil and gas industry is considered in three main sectors<ref name=":3">{{Cite web|last=McClay|first=R.|date=2025-10-12|title=Understanding the Oil and Gas Industry: A Comprehensive Overview|url=https://www.investopedia.com/investing/oil-gas-industry-overview/|url-status=live|website=Investopedia}}</ref>:
{| class="wikitable"
|'''Upstream Sector'''
|'''Midstream Sector'''
|'''Downstream Sector'''
|-
|Include exploration and production. Companies drill for oil and gas.
|Include transportation and usage. Companies handle transit to oil refineries.
|Include refining and distribution. Companies produce refined oil and gas and sell it as gasoline and jet fuel.
|}
Oil and gas consists of hydrocarbons that form naturally within Earth’s crust over millions of years. Organic material derived from plants, animals, and microbes accumulate within depositions, and over geological time, becomes incorporated into sedimentary rocks. These rocks include sandstone, limestone, and shale, and form in ancient oceans. Burial beneath additional sediment subjects organic matter to high temperatures and pressures, leading to the formation of oil and natural gas within the subsurface<ref name=":3" />.

Hydrocarbons may migrate through porous and permeable sedimentary rocks, as they are less dense than surrounding water. An oil and gas reservoir is created when migrating hydrocarbons reach a barrier. These are the types of reservoirs that are used by the petroleum industry by drilling through overlying rocks into the subsurface reservoir<ref name=":3" />.

The petroleum industry is closely related to chemistry and engineering. Geology identifies the source rocks, reservoirs, seals, and migration pathways required for hydrocarbon accumulation, while chemistry helps explain the transformation into petroleum under changing pressure and temperatures. This directly influences engineering decisions related to exploration, production, and resource development. Petroleum systems demonstrate how geological processes create conditions for both chemical and engineering applications.

== Geological Formation ==
The occurrence of oil and gas within the Earth’s crust is demonstrated by a geological framework known as the Total Petroleum System<ref name=":4">{{Cite journal|last=Magoon|first=L. B.|last2=Schmoker|first2=J. W.|date=2000|title=The Total Petroleum System - The Natural Fluid Network that Constrains the Assessment Unit|url=https://pubs.usgs.gov/dds/dds-060/chaps/PS.pdf|journal=United States Geological Survey|pages=1-20}}</ref>. This is the basis for assessing hydrocarbon resources, as it considers both geological elements and processes required for the accumulations to exist. A petroleum system consists of four essential geological elements; source rock, reservoir rock, seal rock, and overburden rock. The essential processes of the Total Petroleum System are generation, migration, accumulation, and trap formation. The first stage of oil and gas formation is hydrocarbon generation within a source rock, defined as the origin of petroleum within the system. The “pod of active source rock” are adjacent source rocks that are responsible for generating hydrocarbons. Under high temperature and pressure conditions, hydrocarbons are expelled from the source rock and into surrounding rock units<ref name=":4" />.

Once generated, hydrocarbons migrate through the subsurface. A petroleum system requires pathways that allow the oil and gas to move from the source rock and into geological formations that can store hydrocarbons. Without migration pathways, generated hydrocarbons would remain trapped within the source rock and accumulations would not form<ref name=":4" />.
[[File:Figure 1. Geological Cross-Section of an OIl and Gas Reservoir.png|thumb|514x514px|Figure 1. Geological Cross-Section of an Oil and Gas Reservoir]]
Hydrocarbons accumulate within the pores of reservoir rocks. Reservoir rocks are essential to the petroleum system since they provide space for hydrocarbon storage. Reservoir characterization studies evaluate properties including porosity and permeability; qualities that dictate the amount of available hydrocarbon storage as well as the ease that fluid can move within the rock. Reservoir rocks with high porosity and permeability are considered more effective at storing hydrocarbons<ref name=":5" />.

For hydrocarbons to remain within a reservoir, a seal rock must also be present. Seal rocks are identified as one of the four essential petroleum system elements because they act as barriers that restrict fluid movement and prevent hydrocarbons from escaping. Additionally, trap formation must occur to retain migrating hydrocarbons. The process of accumulation and trap formation are together required to create and preserve petroleum deposits<ref name=":4" />.

The final essential element of a petroleum system is overburden rock. Overburden refers to the layers of sediment and rock that accumulate above the source rock and reservoir rock over geological time. As additional sediments are deposited, the increasing thickness of overburden subjects underlying rocks to higher temperatures and processes during burial. These conditions influence the thermal maturity of source rocks and play a crucial role in hydrocarbon generation. Therefore, the thickness and burial history over the overburden can be used by geologists to determine whether or not the source rocks have reached the temperature and pressure conditions that are necessary for oil and gas formation<ref name=":4" />.

== Reservoir Quality ==

The presence of a petroleum system alone does not guarantee that hydrocarbons can be recovered economically. Reservoir quality is primarily determined by porosity and permeability, which are considered the fundamental factors of the petroleum reservoir viability. Porosity is the amount of pore space available within a rock for hydrocarbon storage, while permeability describes the degree to which fluids can move through connected pore networks. Reservoir rocks may contain significant pore space but still be considered poor-quality if pore connections are limited. Consequently, both properties must be evaluated when assessing whether or not a reservoir is considered commercially viable. Other important factors of reservoir quality include depositional environment, sediment provenance, weathering, compaction, dissolution, burial depth, pressure, and structural deformation. Since these controls interact over millions of years, reservoir quality reflects cumulative effects, looking back to initial sediment<ref name=":5" />.

One of the most important controls on reservoir quality is the depositional environment in which the sediment was originally deposited. The primary composition of sediment strongly influences the future evolution of reservoir rocks. In sandstone reservoirs, factors such as the source-area geology, climate, topography, and grain size all affect the resulting rock properties. These factors all influence pore space, and therefore impact reservoir quality. Sediments deposited in shallow marine environments often develop better reservoir properties because they tend to be cleaner and contain fewer fine materials that can reduce pore connections. On the other hand, sediments deposited in low-energy environments may contain more clay and silt, which can negatively affect reservoir quality. Well-sorted sediments generally have more interconnected pores than poorly sorted sediments that contain fine grain matrix material<ref name=":5" />.

Different lithologies also respond differently to geological processes. Sandstone reservoirs are among the most common hydrocarbon reservoirs because they can preserve great porosity between sediment grains. Carbonate reservoirs, including limestone and dolostone, often undergo many diagenetic changes through processes such as dissolution, recrystallization, and dolomitization due to their greater chemical reactivity. Rather than relying solely on primary pore space, carbonate reservoirs often develop secondary porosity through diagenesis and fracturing. As a result, both sandstone and carbonate reservoirs often have the capacity to contain hydrocarbons, although having very different pore systems and geological histories<ref name=":5" />.

Following deposition, sediment undergoes diagenesis when physical and chemical changes occur as the sediment is transformed into sedimentary rock. Important stages in reservoir evolution include eodiagenesis (early burial diagenesis), mesodiagenesis (burial diagenesis), and telodiagenesis (uplift-related changes)<ref name=":5" />. During these stages, sediments experience compaction, dissolution, mineral replacement, fracturing, and fluid interactions that can significantly alter reservoir properties. These diagenetic processes can reduce reservoir quality. Compaction during burial decreases pore space as sediment gains become more tightly packed. Chemical compaction and pressure solution may further reduce porosity. Minerals such as quartz, calcite, dolomite, and clay can fill pore spaces and restrict fluid movement. Quartz cementation is identified as one of the most important pore-filling processes in deep buried sandstone reservoirs because of the way it reduces the amount of available pore space progressively. Clay mineral does so similarly and may significantly decrease permeability by blocking pores and restricting fluid flow <ref name=":5">{{Cite journal|last=Worden|first=R. H.|last2=Armitage|first2=P. J.|last3=Butcher|first3=A. R.|last4=Churchill|first4=J. M.|last5=Csoma|first5=A. E.|last6=Hollis|first6=C.|last7=Lander|first7=R. H.|last8=Omma|first8=J. E.|date=2018|title=Petroleum reservoir quality prediction: overview and contrasting approaches from sandstone and carbonate communities|url=https://doi.org/10.1144/SP435.21|journal=Geological Society|volume=435|pages=1-31}}</ref>.

Reservoir quality is not solely determined by burial and porosity. The final characteristics of a reservoir are reflected by the preservation of pore space. Reservoirs with similar depositional origination may exhibit very different porosity and permeability depending on their diagenetic history and the geological conditions they experienced during burial and uplift<ref name=":5" />.
== Oil and Gas Exploration: Seismic Technology ==

Now we know the importance of oil and gas to our society, and how they were formed, the next question is where to locate them. Since reservoirs are below the surface, geologists cannot directly see where they are before drilling. This makes drilling a gamble, and that's where seismic reflection technology contributes to lowering the risk. It works as a tool that helps geologists to create an image of what is beneath the surface before they decide where to drill <ref name=":0">{{Cite journal|last=Mohammed|first=Farfour|date=2016-05-01|title=A review on multicomponent seismology: A potential seismic application for reservoir characterization|url=https://www.sciencedirect.com/science/article/pii/S2090123215001125|journal=Journal of Advanced Research|volume=3|pages=515-524}}</ref>.[[File:Seismic_Survey_and_Mechanism.png|thumb|left|500x500px|Figure 1. Seismic Technology and Mechanism for oil Exploration]]The working principle behind seismic is to use energy waves to explore underground rock layers. During a survey, energy waves are sent into the ground. When waves hit the boundaries between rock layers, some of the energy bounces back to the surface, while some goes further. Receivers then pick up these reflected waves and give information about the depth, shape and arrangement of subsurface layers by analyzing the different waves using the pre-known typical rock’s density and acoustic impedance. After processing, the data can be shown as profiles or 3D seismic images <ref>{{Cite journal|last=Ilya|first=Tsvankin|date=2010-09-01|title=Seismic anisotropy in exploration and reservoir characterization: An overview|url=https://www.researchgate.net/publication/228633261_Seismic_anisotropy_in_exploration_and_reservoir_characterization_An_overview|journal=Geophysics|volume=75}}</ref>.

This is essential because oil and gas need geological structures to build up, and seismic interpretation helps identify these structures. For example, folds show up as layers in seismic images. If the fold creates an anticline, oil and gas might move upward and get trapped near the top. Faults can be spotted when rock layers are broken or displaced. Faults can create traps but might let hydrocarbons escape as well if they aren't sealed properly. So seismic data are not just used to "find oil", they help us understand if subsurface geology has the right structure to store oil and gas<ref>{{Cite journal|last=Lawson|first=M.|date=2018-02-19|title=Geochemical applications in petroleum systems analysis: New constraints and the power of integration|url=https://www.researchgate.net/publication/323282762_Geochemical_applications_in_petroleum_systems_analysis_New_constraints_and_the_power_of_integration|journal=Geological Society, London, Special Publications|volume=468|pages=6}}</ref> . More than locating the reservoir, seismic technology also helps geologists understand its geometry. This includes the shape, thickness, depth and continuity of a reservoir. This matters because a reservoir can be located but not profitable for business. With current technology and the purpose of maximizing the future extraction, geologists are targeting large and continuous reservoirs rather than thin and isolated ones. Seismic data can help pinpoint the drilling target by showing where the reservoir might be thicker or larger<ref name=":0" /> .

An exploration workflow usually starts with a regional study. The first step is for geologists to determine if the region has a petroleum system with possible traps that contain oil. Then there are follow-up seismic surveys to get evidence and more information. Next, geoscientists interpret the data to distinguish geological structures and possible drilling targets. These decisions are assisted by other data, such as core samples. Finally, drilling locations are chosen based on different criteria <ref name=":1">{{Cite journal|last=Ma|first=Yuan Zhe|date=2011-01-01|title=Uncertainty Analysis in Reservoir Characterization and Management: How Much Should We Know About What We Don't Know?|url=https://pubs.geoscienceworld.org/aapg/books/edited-volume/1248/chapter-abstract/107059711/Uncertainty-Analysis-in-Reservoir-Characterization?redirectedFrom=fulltext|journal=AAPG Memoir|volume=1|pages=15}}</ref>.

However, seismic technology is not perfect. As an imaging technique that relies on the reflection of waves, some thin reservoirs or structures can be hard to detect. Also, seismic data cannot directly show the oil and gas but uses structures to infer their existence. Based on this limitation, seismic technology is more like a tool that reduces drilling risk than eliminates all uncertainties <ref>Saad, M. R., & Jadeer, A.-S. (2022). ''Seismic Method for Exploration Oil and Gas Reservoirs''. <nowiki>https://doi.org/10.1007/978-981-99-1964-2_89</nowiki></ref>.

== Oil and Gas Extraction: How Geology Determines Engineering Decisions ==
Once an oil reservoir is proven as continuous and profitable, geology still plays a role in deciding how to extract the resources. In a word, engineering decisions and extraction methods are based on how the subsurface looks and how fluids move through the rock.

Engineers need more geology information before deciding where to drill. They want to know the depth of the potential drilling trajectory, the thickness of the oil reservoir, and the fluid contacts of the reservoir to optimize the performance. For example, a rich oil-bearing zone in the reservoir should be the highest priority to place the well nearby. However, if the zone is disrupted by some faults, then engineers and geologists must determine whether these faults connect to parts of the reservoir or cut it into separate parts. Moreover, if the production well is too close to a water or gas zone, a water or gas breakthrough is likely to happen and reduce oil production. In a real-world case, a breakthrough can easily turn a high-production well into a shut-down.
[[File:Reservori_Simulation_Model.jpg|thumb|Figure 2. The reservoir modeling workflow showing the sequence of stages in data acquisition and interpretation<ref name=":2">Abel, M., Garcia, L., Lorenzatti, A., & De Ros, L. (2010, October 26). ''SEMANTIC INTEROPERABILITY IN THE PETROLEUM CHAIN: THE CONTRIBUTION OF ONTOLOGICAL ANALYSIS''.</ref>|549x549px]]Reservoir simulation is a great tool to use in oil extraction, just like how seismic technology assists oil exploration. A reservoir model is a digital version of a reservoir with a vivid representation of reservoir structures and various relevant properties like pressure, permeability, porosity, and saturation of each phase. Engineers use this model to predict how the reservoir might behave during production. For instance, the model can estimate production rates, pressure changes, and any potential water cut. It can also achieve optimization on certain jobs, like comparing different production plans and well placement strategies. Since the model is built purely based on geological data, its quality varies depending on how well the regional geology is captured and understood, and this can also be a limitation of the reservoir model <ref name=":2" /><ref>Sambo, C., Iferobia, C. C., Babasafari, A. A., Rezaei, S., & Akanni, O. A. (2020). The Role of Time Lapse(4D) Seismic Technology as Reservoir Monitoring and Surveillance Tool: A Comprehensive Review. ''Journal of Natural Gas Science and Engineering'', ''80'', 103312. <nowiki>https://doi.org/10.1016/j.jngse.2020.103312</nowiki></ref>.

Since there are many different types of reservoirs, extraction methods have also been developed differently to achieve efficient production for each case. And they can be separated under two main reservoir types: conventional and unconventional.
{| class="wikitable"
|+
!Reservoir Type
!Geological Characteristics
!Main Extraction Methods
!Engineering
Reason
|-
|Conventional reservoirs
|High permeability and porosity for fluids to flow naturally toward the well through connected pore spaces
|Primary production relies on natural reservoir pressure and secondary recovery methods like water injection are used to maintain the pressure
|Maintain and increase reservoir pressure to improve flow toward production wells
|-
|Unconventional reservoirs
|Low permeability so fluids are trapped in rocks or exist as highly viscous bitumen
|Horizontal drilling and hydraulic fracturing are commonly used for shale gas and tight oil
For deep oil sands, steam-assisted gravity drainage can be used by injecting steam underground to heat bitumen and lower the viscousity
|Create flow pathways to make hydrocarbons mobile enough to be produced
|}
Overall, geology has a strong influence on engineering decisions in oil and gas extraction. Geology informs engineers to know the reservoir quality, what extraction methodology can be applied, and what risks might exist during production. Geological information has also been integrated into reservoir models to provide a more in-depth understanding and optimization. Oil extraction is not just about improving equipment and technology, it is also a process in which geological knowledge is applied with engineering decisions.

== Chemical Engineering and Petroleum Products ==
[[File:Fractional Distillation.jpg|thumb|Fractional Distillation Process of Crude Oil (Wigmore Trading, n.d.)|512x512px]]
Crude oil, in its unrefined state, has almost no direct utility due to its highly complex molecular constitution. It exists fundamentally as a dense, complex mixture of hundreds of different hydrocarbons. The three basic components of crude oil are alkanes, cycloalkanes, and aromatics. The primary steps of chemical engineering within petroleum refineries are physical separation and chemical conversion. The first step separates the heterogeneous mixture into narrower, manageable fractions based on physical properties, and the second step upgrades these fractions into high-value, commercially viable products. This transformation from raw, unusable crude oil into high-value fuels relies on a sequence of thermal processes and complex catalytic reactions that manipulate molecular structures. (Sani et al., 2024)

The foundational stage of any refinery configuration is fractional distillation. It depends on the differential volatility and boiling points of the constituent hydrocarbons within crude oil. The process is commonly operationalized through the Atmospheric Distillation Unit: crude oil is preheated to approximately 350-400°C and pumped into the lowest and hottest level in the Fractional distillation tower. As the vaporized oil ascends through a series of distillation trays with temperature decreasing, it cools progressively. Hydrocarbons with lower boiling points condense at higher levels of the tower. This allows the continuous withdrawal of light fractions such as liquefied petroleum gas, naphtha, kerosene, and gas oil. (Sani et al., 2024)

Since the initial fractions obtained from atmospheric distillation are mostly the result of physical separation, they can't break the products into smaller molecules. Those distilled heavy molecules are hardly suitable for the commercial market. Thus, refineries rely heavily on cracking processes to convert these high-molecular-weight hydrocarbons into higher-value, lighter liquid fuels. This process involves the thermal or catalytic breaking of carbon-carbon covalent bonds in long-chain alkanes. Modern chemical engineering uses Fluid Catalytic Cracking (FCC) as the primary process. The market prefers this method due to its ability to maximize high-value gasoline yields from heavy gas oils. The efficiency of FCC is highly influenced by the use of highly active, acidic zeolite catalysts. Zeolite selectively accelerates secondary hydrocarbon cracking while minimizing unwanted coke formation. Alternatively, for middle distillates such as jet fuel and diesel, hydrocracking is used. This process takes place in a high-temperature, high-pressure, hydrogen-rich environment. Over catalysts, the hydrogen saturates aromatic rings and breaks the carbon chains. (Sani et al., 2024)

Reforming is another chemical process that changes a molecule's structure without altering the overall number of carbon atoms. This method is mainly used for straight-run naphtha, a distillation product. Straight-run naphtha has a suitable molecular size for vehicle engines, but the straight-chain alkanes it contains can cause knocking. Reforming uses chemical reactions to trigger isomerization, cyclization or dehydration of the straight chains. During catalytic reforming, a large amount of hydrogen is formed as a byproduct of dehydrogenation. This is great in the engineering industry, since hydrogen can be pumped straight to hydrotreating. Hydrotreating is a process for purifying. Crude oil naturally contains heteroatom impurities like sulphur, nitrogen, and heavy metals. With the purification process, SOx and NOx won't be released during burning, thereby preventing catalyst poisoning. Under high pressure and temperature, hydrogen can convert sulphur and nitrogen into H2S and NH3, separating the impurities completely. (Sani et al., 2024)

Through the physical separations and chemical alterations described above, crude oil ultimately becomes market products and plays an important role in the global economy. These outputs are broadly divided into three categories: transportation fuels, industrial specialty products, and petrochemical feedstocks. Transportation fuels such as gasoline, diesel, and kerosene sustain global logistics and transportation networks daily. They determine whether the international trade markets can function efficiently. Industrial specialty products like asphalt, which is extracted from heavy residues, play an indispensable role as the structural binder in global infrastructure development. Nevertheless, according to Levi et al. (2018), straight-run naphtha, serving as a petrochemical feedstock, has been a source for the global chemical industry. Through steam cracking, primary light olefins and aromatics are synthesized. Thus, downstream polymerization can convert them into ubiquitous materials such as polyethylene, polypropylene, and synthetic rubbers. (Levi et al., 2018)

== Environmental issues ==
When it comes to gas and oil extraction, environmental concerns are always on the table. Is the project sustainable? Will the extraction cause any irreparable damage to the Earth's environment? Are the operations negatively affecting other living beings' natural habitats? These are all the questions that geologists and engineers constantly ask themselves. To comprehensively assess environmental issues, both onshore and offshore oil and gas developments must be considered.

Onshore operations are raising the risks of induced earthquakes. Engineering techniques used in unconventional reservoirs, such as hydraulic fracturing and wastewater injection, alter subsurface pore-fluid pressure and reduce the shear strength of the original faults. This may increase the possibility of fault slippage, thus triggering seismic events. This phenomenon is particularly frequent in areas with active shale gas extraction. A case study in the Western Canada Sedimentary Basin (WCSB) in northeastern British Columbia, Canada, shows that the high-density hydraulic fracturing and fluid reinjection activities have led to a significant increase in regional background seismicity in recent years. (Pozzobon et al., 2023)[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Conclusion / Your Evaluation of the Connections==

=== Conclusion: ===

=== Breakdown of group contributions: ===
Marijke:

* Introduction to Petroleum Systems
* Geological Formation
* Reservoir Quality

Jack:

* Oil and Gas Exploration: Seismic Technology
* Oil and Gas Extraction: How Geology Determines Engineering Decisions
Keming:
* Chemical Engineering and Petroleum Products
* Environmental Issues

=== AI Statement: ===
AI tools were used to support brainstorming ideas and to delegate portions within the group. AI-generated images are used and cited. All final written content have been created and reviewed by all group members.

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-17T22:35:10Z

KemingWu: /* Environmental issues */

==Introduction to Petroleum Systems==

Oil and natural gas are among the most important geological resources utilized by modern society. This industry fuels the global economy and energy is used for electricity, transportation, and industrial manufacturing. The oil and gas industry is considered in three main sectors<ref name=":3">{{Cite web|last=McClay|first=R.|date=2025-10-12|title=Understanding the Oil and Gas Industry: A Comprehensive Overview|url=https://www.investopedia.com/investing/oil-gas-industry-overview/|url-status=live|website=Investopedia}}</ref>:
{| class="wikitable"
|'''Upstream Sector'''
|'''Midstream Sector'''
|'''Downstream Sector'''
|-
|Include exploration and production. Companies drill for oil and gas.
|Include transportation and usage. Companies handle transit to oil refineries.
|Include refining and distribution. Companies produce refined oil and gas and sell it as gasoline and jet fuel.
|}
Oil and gas consists of hydrocarbons that form naturally within Earth’s crust over millions of years. Organic material derived from plants, animals, and microbes accumulate within depositions, and over geological time, becomes incorporated into sedimentary rocks. These rocks include sandstone, limestone, and shale, and form in ancient oceans. Burial beneath additional sediment subjects organic matter to high temperatures and pressures, leading to the formation of oil and natural gas within the subsurface<ref name=":3" />.

Hydrocarbons may migrate through porous and permeable sedimentary rocks, as they are less dense than surrounding water. An oil and gas reservoir is created when migrating hydrocarbons reach a barrier. These are the types of reservoirs that are used by the petroleum industry by drilling through overlying rocks into the subsurface reservoir<ref name=":3" />.

The petroleum industry is closely related to chemistry and engineering. Geology identifies the source rocks, reservoirs, seals, and migration pathways required for hydrocarbon accumulation, while chemistry helps explain the transformation into petroleum under changing pressure and temperatures. This directly influences engineering decisions related to exploration, production, and resource development. Petroleum systems demonstrate how geological processes create conditions for both chemical and engineering applications.

== Geological Formation ==
The occurrence of oil and gas within the Earth’s crust is demonstrated by a geological framework known as the Total Petroleum System<ref name=":4">{{Cite journal|last=Magoon|first=L. B.|last2=Schmoker|first2=J. W.|date=2000|title=The Total Petroleum System - The Natural Fluid Network that Constrains the Assessment Unit|url=https://pubs.usgs.gov/dds/dds-060/chaps/PS.pdf|journal=United States Geological Survey|pages=1-20}}</ref>. This is the basis for assessing hydrocarbon resources, as it considers both geological elements and processes required for the accumulations to exist. A petroleum system consists of four essential geological elements; source rock, reservoir rock, seal rock, and overburden rock. The essential processes of the Total Petroleum System are generation, migration, accumulation, and trap formation. The first stage of oil and gas formation is hydrocarbon generation within a source rock, defined as the origin of petroleum within the system. The “pod of active source rock” are adjacent source rocks that are responsible for generating hydrocarbons. Under high temperature and pressure conditions, hydrocarbons are expelled from the source rock and into surrounding rock units<ref name=":4" />.

Once generated, hydrocarbons migrate through the subsurface. A petroleum system requires pathways that allow the oil and gas to move from the source rock and into geological formations that can store hydrocarbons. Without migration pathways, generated hydrocarbons would remain trapped within the source rock and accumulations would not form<ref name=":4" />.
[[File:Figure 1. Geological Cross-Section of an OIl and Gas Reservoir.png|thumb|514x514px|Figure 1. Geological Cross-Section of an Oil and Gas Reservoir]]
Hydrocarbons accumulate within the pores of reservoir rocks. Reservoir rocks are essential to the petroleum system since they provide space for hydrocarbon storage. Reservoir characterization studies evaluate properties including porosity and permeability; qualities that dictate the amount of available hydrocarbon storage as well as the ease that fluid can move within the rock. Reservoir rocks with high porosity and permeability are considered more effective at storing hydrocarbons<ref name=":5" />.

For hydrocarbons to remain within a reservoir, a seal rock must also be present. Seal rocks are identified as one of the four essential petroleum system elements because they act as barriers that restrict fluid movement and prevent hydrocarbons from escaping. Additionally, trap formation must occur to retain migrating hydrocarbons. The process of accumulation and trap formation are together required to create and preserve petroleum deposits<ref name=":4" />.

The final essential element of a petroleum system is overburden rock. Overburden refers to the layers of sediment and rock that accumulate above the source rock and reservoir rock over geological time. As additional sediments are deposited, the increasing thickness of overburden subjects underlying rocks to higher temperatures and processes during burial. These conditions influence the thermal maturity of source rocks and play a crucial role in hydrocarbon generation. Therefore, the thickness and burial history over the overburden can be used by geologists to determine whether or not the source rocks have reached the temperature and pressure conditions that are necessary for oil and gas formation<ref name=":4" />.

== Reservoir Quality ==

The presence of a petroleum system alone does not guarantee that hydrocarbons can be recovered economically. Reservoir quality is primarily determined by porosity and permeability, which are considered the fundamental factors of the petroleum reservoir viability. Porosity is the amount of pore space available within a rock for hydrocarbon storage, while permeability describes the degree to which fluids can move through connected pore networks. Reservoir rocks may contain significant pore space but still be considered poor-quality if pore connections are limited. Consequently, both properties must be evaluated when assessing whether or not a reservoir is considered commercially viable. Other important factors of reservoir quality include depositional environment, sediment provenance, weathering, compaction, dissolution, burial depth, pressure, and structural deformation. Since these controls interact over millions of years, reservoir quality reflects cumulative effects, looking back to initial sediment<ref name=":5" />.

One of the most important controls on reservoir quality is the depositional environment in which the sediment was originally deposited. The primary composition of sediment strongly influences the future evolution of reservoir rocks. In sandstone reservoirs, factors such as the source-area geology, climate, topography, and grain size all affect the resulting rock properties. These factors all influence pore space, and therefore impact reservoir quality. Sediments deposited in shallow marine environments often develop better reservoir properties because they tend to be cleaner and contain fewer fine materials that can reduce pore connections. On the other hand, sediments deposited in low-energy environments may contain more clay and silt, which can negatively affect reservoir quality. Well-sorted sediments generally have more interconnected pores than poorly sorted sediments that contain fine grain matrix material<ref name=":5" />.

Different lithologies also respond differently to geological processes. Sandstone reservoirs are among the most common hydrocarbon reservoirs because they can preserve great porosity between sediment grains. Carbonate reservoirs, including limestone and dolostone, often undergo many diagenetic changes through processes such as dissolution, recrystallization, and dolomitization due to their greater chemical reactivity. Rather than relying solely on primary pore space, carbonate reservoirs often develop secondary porosity through diagenesis and fracturing. As a result, both sandstone and carbonate reservoirs often have the capacity to contain hydrocarbons, although having very different pore systems and geological histories<ref name=":5" />.

Following deposition, sediment undergoes diagenesis when physical and chemical changes occur as the sediment is transformed into sedimentary rock. Important stages in reservoir evolution include eodiagenesis (early burial diagenesis), mesodiagenesis (burial diagenesis), and telodiagenesis (uplift-related changes)<ref name=":5" />. During these stages, sediments experience compaction, dissolution, mineral replacement, fracturing, and fluid interactions that can significantly alter reservoir properties. These diagenetic processes can reduce reservoir quality. Compaction during burial decreases pore space as sediment gains become more tightly packed. Chemical compaction and pressure solution may further reduce porosity. Minerals such as quartz, calcite, dolomite, and clay can fill pore spaces and restrict fluid movement. Quartz cementation is identified as one of the most important pore-filling processes in deep buried sandstone reservoirs because of the way it reduces the amount of available pore space progressively. Clay mineral does so similarly and may significantly decrease permeability by blocking pores and restricting fluid flow <ref name=":5">{{Cite journal|last=Worden|first=R. H.|last2=Armitage|first2=P. J.|last3=Butcher|first3=A. R.|last4=Churchill|first4=J. M.|last5=Csoma|first5=A. E.|last6=Hollis|first6=C.|last7=Lander|first7=R. H.|last8=Omma|first8=J. E.|date=2018|title=Petroleum reservoir quality prediction: overview and contrasting approaches from sandstone and carbonate communities|url=https://doi.org/10.1144/SP435.21|journal=Geological Society|volume=435|pages=1-31}}</ref>.

Reservoir quality is not solely determined by burial and porosity. The final characteristics of a reservoir are reflected by the preservation of pore space. Reservoirs with similar depositional origination may exhibit very different porosity and permeability depending on their diagenetic history and the geological conditions they experienced during burial and uplift<ref name=":5" />.
== Oil and Gas Exploration: Seismic Technology ==

Now we know the importance of oil and gas to our society, and how they were formed, the next question is where to locate them. Since reservoirs are below the surface, geologists cannot directly see where they are before drilling. This makes drilling a gamble, and that's where seismic reflection technology contributes to lowering the risk. It works as a tool that helps geologists to create an image of what is beneath the surface before they decide where to drill <ref name=":0">{{Cite journal|last=Mohammed|first=Farfour|date=2016-05-01|title=A review on multicomponent seismology: A potential seismic application for reservoir characterization|url=https://www.sciencedirect.com/science/article/pii/S2090123215001125|journal=Journal of Advanced Research|volume=3|pages=515-524}}</ref>.[[File:Seismic_Survey_and_Mechanism.png|thumb|left|500x500px|Figure 1. Seismic Technology and Mechanism for oil Exploration]]The working principle behind seismic is to use energy waves to explore underground rock layers. During a survey, energy waves are sent into the ground. When waves hit the boundaries between rock layers, some of the energy bounces back to the surface, while some goes further. Receivers then pick up these reflected waves and give information about the depth, shape and arrangement of subsurface layers by analyzing the different waves using the pre-known typical rock’s density and acoustic impedance. After processing, the data can be shown as profiles or 3D seismic images <ref>{{Cite journal|last=Ilya|first=Tsvankin|date=2010-09-01|title=Seismic anisotropy in exploration and reservoir characterization: An overview|url=https://www.researchgate.net/publication/228633261_Seismic_anisotropy_in_exploration_and_reservoir_characterization_An_overview|journal=Geophysics|volume=75}}</ref>.

This is essential because oil and gas need geological structures to build up, and seismic interpretation helps identify these structures. For example, folds show up as layers in seismic images. If the fold creates an anticline, oil and gas might move upward and get trapped near the top. Faults can be spotted when rock layers are broken or displaced. Faults can create traps but might let hydrocarbons escape as well if they aren't sealed properly. So seismic data are not just used to "find oil", they help us understand if subsurface geology has the right structure to store oil and gas<ref>{{Cite journal|last=Lawson|first=M.|date=2018-02-19|title=Geochemical applications in petroleum systems analysis: New constraints and the power of integration|url=https://www.researchgate.net/publication/323282762_Geochemical_applications_in_petroleum_systems_analysis_New_constraints_and_the_power_of_integration|journal=Geological Society, London, Special Publications|volume=468|pages=6}}</ref> . More than locating the reservoir, seismic technology also helps geologists understand its geometry. This includes the shape, thickness, depth and continuity of a reservoir. This matters because a reservoir can be located but not profitable for business. With current technology and the purpose of maximizing the future extraction, geologists are targeting large and continuous reservoirs rather than thin and isolated ones. Seismic data can help pinpoint the drilling target by showing where the reservoir might be thicker or larger<ref name=":0" /> .

An exploration workflow usually starts with a regional study. The first step is for geologists to determine if the region has a petroleum system with possible traps that contain oil. Then there are follow-up seismic surveys to get evidence and more information. Next, geoscientists interpret the data to distinguish geological structures and possible drilling targets. These decisions are assisted by other data, such as core samples. Finally, drilling locations are chosen based on different criteria <ref name=":1">{{Cite journal|last=Ma|first=Yuan Zhe|date=2011-01-01|title=Uncertainty Analysis in Reservoir Characterization and Management: How Much Should We Know About What We Don't Know?|url=https://pubs.geoscienceworld.org/aapg/books/edited-volume/1248/chapter-abstract/107059711/Uncertainty-Analysis-in-Reservoir-Characterization?redirectedFrom=fulltext|journal=AAPG Memoir|volume=1|pages=15}}</ref>.

However, seismic technology is not perfect. As an imaging technique that relies on the reflection of waves, some thin reservoirs or structures can be hard to detect. Also, seismic data cannot directly show the oil and gas but uses structures to infer their existence. Based on this limitation, seismic technology is more like a tool that reduces drilling risk than eliminates all uncertainties <ref>Saad, M. R., & Jadeer, A.-S. (2022). ''Seismic Method for Exploration Oil and Gas Reservoirs''. <nowiki>https://doi.org/10.1007/978-981-99-1964-2_89</nowiki></ref>.

== Oil and Gas Extraction: How Geology Determines Engineering Decisions ==
Once an oil reservoir is proven as continuous and profitable, geology still plays a role in deciding how to extract the resources. In a word, engineering decisions and extraction methods are based on how the subsurface looks and how fluids move through the rock.

Engineers need more geology information before deciding where to drill. They want to know the depth of the potential drilling trajectory, the thickness of the oil reservoir, and the fluid contacts of the reservoir to optimize the performance. For example, a rich oil-bearing zone in the reservoir should be the highest priority to place the well nearby. However, if the zone is disrupted by some faults, then engineers and geologists must determine whether these faults connect to parts of the reservoir or cut it into separate parts. Moreover, if the production well is too close to a water or gas zone, a water or gas breakthrough is likely to happen and reduce oil production. In a real-world case, a breakthrough can easily turn a high-production well into a shut-down.
[[File:Reservori_Simulation_Model.jpg|thumb|Figure 2. The reservoir modeling workflow showing the sequence of stages in data acquisition and interpretation<ref name=":2">Abel, M., Garcia, L., Lorenzatti, A., & De Ros, L. (2010, October 26). ''SEMANTIC INTEROPERABILITY IN THE PETROLEUM CHAIN: THE CONTRIBUTION OF ONTOLOGICAL ANALYSIS''.</ref>|549x549px]]Reservoir simulation is a great tool to use in oil extraction, just like how seismic technology assists oil exploration. A reservoir model is a digital version of a reservoir with a vivid representation of reservoir structures and various relevant properties like pressure, permeability, porosity, and saturation of each phase. Engineers use this model to predict how the reservoir might behave during production. For instance, the model can estimate production rates, pressure changes, and any potential water cut. It can also achieve optimization on certain jobs, like comparing different production plans and well placement strategies. Since the model is built purely based on geological data, its quality varies depending on how well the regional geology is captured and understood, and this can also be a limitation of the reservoir model <ref name=":2" /><ref>Sambo, C., Iferobia, C. C., Babasafari, A. A., Rezaei, S., & Akanni, O. A. (2020). The Role of Time Lapse(4D) Seismic Technology as Reservoir Monitoring and Surveillance Tool: A Comprehensive Review. ''Journal of Natural Gas Science and Engineering'', ''80'', 103312. <nowiki>https://doi.org/10.1016/j.jngse.2020.103312</nowiki></ref>.

Since there are many different types of reservoirs, extraction methods have also been developed differently to achieve efficient production for each case. And they can be separated under two main reservoir types: conventional and unconventional.
{| class="wikitable"
|+
!Reservoir Type
!Geological Characteristics
!Main Extraction Methods
!Engineering
Reason
|-
|Conventional reservoirs
|High permeability and porosity for fluids to flow naturally toward the well through connected pore spaces
|Primary production relies on natural reservoir pressure and secondary recovery methods like water injection are used to maintain the pressure
|Maintain and increase reservoir pressure to improve flow toward production wells
|-
|Unconventional reservoirs
|Low permeability so fluids are trapped in rocks or exist as highly viscous bitumen
|Horizontal drilling and hydraulic fracturing are commonly used for shale gas and tight oil
For deep oil sands, steam-assisted gravity drainage can be used by injecting steam underground to heat bitumen and lower the viscousity
|Create flow pathways to make hydrocarbons mobile enough to be produced
|}
Overall, geology has a strong influence on engineering decisions in oil and gas extraction. Geology informs engineers to know the reservoir quality, what extraction methodology can be applied, and what risks might exist during production. Geological information has also been integrated into reservoir models to provide a more in-depth understanding and optimization. Oil extraction is not just about improving equipment and technology, it is also a process in which geological knowledge is applied with engineering decisions.

== Chemical Engineering and Petroleum Products ==
[[File:Fractional Distillation.jpg|thumb|Fractional Distillation Process of Crude Oil (Wigmore Trading, n.d.)|512x512px]]
Crude oil, in its unrefined state, has almost no direct utility due to its highly complex molecular constitution. It exists fundamentally as a dense, complex mixture of hundreds of different hydrocarbons. The three basic components of crude oil are alkanes, cycloalkanes, and aromatics. The primary steps of chemical engineering within petroleum refineries are physical separation and chemical conversion. The first step separates the heterogeneous mixture into narrower, manageable fractions based on physical properties, and the second step upgrades these fractions into high-value, commercially viable products. This transformation from raw, unusable crude oil into high-value fuels relies on a sequence of thermal processes and complex catalytic reactions that manipulate molecular structures. (Sani et al., 2024)

The foundational stage of any refinery configuration is fractional distillation. It depends on the differential volatility and boiling points of the constituent hydrocarbons within crude oil. The process is commonly operationalized through the Atmospheric Distillation Unit: crude oil is preheated to approximately 350-400°C and pumped into the lowest and hottest level in the Fractional distillation tower. As the vaporized oil ascends through a series of distillation trays with temperature decreasing, it cools progressively. Hydrocarbons with lower boiling points condense at higher levels of the tower. This allows the continuous withdrawal of light fractions such as liquefied petroleum gas, naphtha, kerosene, and gas oil. (Sani et al., 2024)

Since the initial fractions obtained from atmospheric distillation are mostly the result of physical separation, they can't break the products into smaller molecules. Those distilled heavy molecules are hardly suitable for the commercial market. Thus, refineries rely heavily on cracking processes to convert these high-molecular-weight hydrocarbons into higher-value, lighter liquid fuels. This process involves the thermal or catalytic breaking of carbon-carbon covalent bonds in long-chain alkanes. Modern chemical engineering uses Fluid Catalytic Cracking (FCC) as the primary process. The market prefers this method due to its ability to maximize high-value gasoline yields from heavy gas oils. The efficiency of FCC is highly influenced by the use of highly active, acidic zeolite catalysts. Zeolite selectively accelerates secondary hydrocarbon cracking while minimizing unwanted coke formation. Alternatively, for middle distillates such as jet fuel and diesel, hydrocracking is used. This process takes place in a high-temperature, high-pressure, hydrogen-rich environment. Over catalysts, the hydrogen saturates aromatic rings and breaks the carbon chains. (Sani et al., 2024)

Reforming is another chemical process that changes a molecule's structure without altering the overall number of carbon atoms. This method is mainly used for straight-run naphtha, a distillation product. Straight-run naphtha has a suitable molecular size for vehicle engines, but the straight-chain alkanes it contains can cause knocking. Reforming uses chemical reactions to trigger isomerization, cyclization or dehydration of the straight chains. During catalytic reforming, a large amount of hydrogen is formed as a byproduct of dehydrogenation. This is great in the engineering industry, since hydrogen can be pumped straight to hydrotreating. Hydrotreating is a process for purifying. Crude oil naturally contains heteroatom impurities like sulphur, nitrogen, and heavy metals. With the purification process, SOx and NOx won't be released during burning, thereby preventing catalyst poisoning. Under high pressure and temperature, hydrogen can convert sulphur and nitrogen into H2S and NH3, separating the impurities completely. (Sani et al., 2024)

Through the physical separations and chemical alterations described above, crude oil ultimately becomes market products and plays an important role in the global economy. These outputs are broadly divided into three categories: transportation fuels, industrial specialty products, and petrochemical feedstocks. Transportation fuels such as gasoline, diesel, and kerosene sustain global logistics and transportation networks daily. They determine whether the international trade markets can function efficiently. Industrial specialty products like asphalt, which is extracted from heavy residues, play an indispensable role as the structural binder in global infrastructure development. Nevertheless, according to Levi et al. (2018), straight-run naphtha, serving as a petrochemical feedstock, has been a source for the global chemical industry. Through steam cracking, primary light olefins and aromatics are synthesized. Thus, downstream polymerization can convert them into ubiquitous materials such as polyethylene, polypropylene, and synthetic rubbers. (Levi et al., 2018)

== Environmental issues ==
When it comes to gas and oil extraction, environmental concerns are always on the table. Is the project sustainable? Will the extraction cause any irreparable damage to the Earth's environment? Are the operations negatively affecting other living beings' natural habitats? These are all the questions that geologists and engineers constantly ask themselves. To comprehensively assess environmental issues, both onshore and offshore oil and gas developments must be considered.

Onshore operations are raising the risks of induced earthquakes. Subsurface fluid Injection alters pore fluid pressure and reduces the shear strength of the original faults. This may increase the possibility of fault slippage, thus triggering seismic events. (Pozzobon et al., 2023)[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Conclusion / Your Evaluation of the Connections==

=== Conclusion: ===

=== Breakdown of group contributions: ===
Marijke:

* Introduction to Petroleum Systems
* Geological Formation
* Reservoir Quality

Jack:

* Oil and Gas Exploration: Seismic Technology
* Oil and Gas Extraction: How Geology Determines Engineering Decisions
Keming:
* Chemical Engineering and Petroleum Products
* Environmental Issues

=== AI Statement: ===
AI tools were used to support brainstorming ideas and to delegate portions within the group. AI-generated images are used and cited. All final written content have been created and reviewed by all group members.

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-17T21:52:41Z

KemingWu: /* Chemical Engineering and Petroleum Products */

==Introduction to Petroleum Systems==

Oil and natural gas are among the most important geological resources utilized by modern society. This industry fuels the global economy and energy is used for electricity, transportation, and industrial manufacturing. The oil and gas industry is considered in three main sectors<ref name=":3">{{Cite web|last=McClay|first=R.|date=2025-10-12|title=Understanding the Oil and Gas Industry: A Comprehensive Overview|url=https://www.investopedia.com/investing/oil-gas-industry-overview/|url-status=live|website=Investopedia}}</ref>:
{| class="wikitable"
|'''Upstream Sector'''
|'''Midstream Sector'''
|'''Downstream Sector'''
|-
|Include exploration and production. Companies drill for oil and gas.
|Include transportation and usage. Companies handle transit to oil refineries.
|Include refining and distribution. Companies produce refined oil and gas and sell it as gasoline and jet fuel.
|}
Oil and gas consists of hydrocarbons that form naturally within Earth’s crust over millions of years. Organic material derived from plants, animals, and microbes accumulate within depositions, and over geological time, becomes incorporated into sedimentary rocks. These rocks include sandstone, limestone, and shale, and form in ancient oceans. Burial beneath additional sediment subjects organic matter to high temperatures and pressures, leading to the formation of oil and natural gas within the subsurface<ref name=":3" />.

Hydrocarbons may migrate through porous and permeable sedimentary rocks, as they are less dense than surrounding water. An oil and gas reservoir is created when migrating hydrocarbons reach a barrier. These are the types of reservoirs that are used by the petroleum industry by drilling through overlying rocks into the subsurface reservoir<ref name=":3" />.

The petroleum industry is closely related to chemistry and engineering. Geology identifies the source rocks, reservoirs, seals, and migration pathways required for hydrocarbon accumulation, while chemistry helps explain the transformation into petroleum under changing pressure and temperatures. This directly influences engineering decisions related to exploration, production, and resource development. Petroleum systems demonstrate how geological processes create conditions for both chemical and engineering applications.

== Geological Formation ==
The occurrence of oil and gas within the Earth’s crust is demonstrated by a geological framework known as the Total Petroleum System<ref name=":4">{{Cite journal|last=Magoon|first=L. B.|last2=Schmoker|first2=J. W.|date=2000|title=The Total Petroleum System - The Natural Fluid Network that Constrains the Assessment Unit|url=https://pubs.usgs.gov/dds/dds-060/chaps/PS.pdf|journal=United States Geological Survey|pages=1-20}}</ref>. This is the basis for assessing hydrocarbon resources, as it considers both geological elements and processes required for the accumulations to exist. A petroleum system consists of four essential geological elements; source rock, reservoir rock, seal rock, and overburden rock. The essential processes of the Total Petroleum System are generation, migration, accumulation, and trap formation. The first stage of oil and gas formation is hydrocarbon generation within a source rock, defined as the origin of petroleum within the system. The “pod of active source rock” are adjacent source rocks that are responsible for generating hydrocarbons. Under high temperature and pressure conditions, hydrocarbons are expelled from the source rock and into surrounding rock units<ref name=":4" />.

Once generated, hydrocarbons migrate through the subsurface. A petroleum system requires pathways that allow the oil and gas to move from the source rock and into geological formations that can store hydrocarbons. Without migration pathways, generated hydrocarbons would remain trapped within the source rock and accumulations would not form<ref name=":4" />.
[[File:Figure 1. Geological Cross-Section of an OIl and Gas Reservoir.png|thumb|514x514px|Figure 1. Geological Cross-Section of an Oil and Gas Reservoir]]
Hydrocarbons accumulate within the pores of reservoir rocks. Reservoir rocks are essential to the petroleum system since they provide space for hydrocarbon storage. Reservoir characterization studies evaluate properties including porosity and permeability; qualities that dictate the amount of available hydrocarbon storage as well as the ease that fluid can move within the rock. Reservoir rocks with high porosity and permeability are considered more effective at storing hydrocarbons<ref name=":5" />.

For hydrocarbons to remain within a reservoir, a seal rock must also be present. Seal rocks are identified as one of the four essential petroleum system elements because they act as barriers that restrict fluid movement and prevent hydrocarbons from escaping. Additionally, trap formation must occur to retain migrating hydrocarbons. The process of accumulation and trap formation are together required to create and preserve petroleum deposits<ref name=":4" />.

The final essential element of a petroleum system is overburden rock. Overburden refers to the layers of sediment and rock that accumulate above the source rock and reservoir rock over geological time. As additional sediments are deposited, the increasing thickness of overburden subjects underlying rocks to higher temperatures and processes during burial. These conditions influence the thermal maturity of source rocks and play a crucial role in hydrocarbon generation. Therefore, the thickness and burial history over the overburden can be used by geologists to determine whether or not the source rocks have reached the temperature and pressure conditions that are necessary for oil and gas formation<ref name=":4" />.

== Reservoir Quality ==

The presence of a petroleum system alone does not guarantee that hydrocarbons can be recovered economically. Reservoir quality is primarily determined by porosity and permeability, which are considered the fundamental factors of the petroleum reservoir viability. Porosity is the amount of pore space available within a rock for hydrocarbon storage, while permeability describes the degree to which fluids can move through connected pore networks. Reservoir rocks may contain significant pore space but still be considered poor-quality if pore connections are limited. Consequently, both properties must be evaluated when assessing whether or not a reservoir is considered commercially viable. Other important factors of reservoir quality include depositional environment, sediment provenance, weathering, compaction, dissolution, burial depth, pressure, and structural deformation. Since these controls interact over millions of years, reservoir quality reflects cumulative effects, looking back to initial sediment<ref name=":5" />.

One of the most important controls on reservoir quality is the depositional environment in which the sediment was originally deposited. The primary composition of sediment strongly influences the future evolution of reservoir rocks. In sandstone reservoirs, factors such as the source-area geology, climate, topography, and grain size all affect the resulting rock properties. These factors all influence pore space, and therefore impact reservoir quality. Sediments deposited in shallow marine environments often develop better reservoir properties because they tend to be cleaner and contain fewer fine materials that can reduce pore connections. On the other hand, sediments deposited in low-energy environments may contain more clay and silt, which can negatively affect reservoir quality. Well-sorted sediments generally have more interconnected pores than poorly sorted sediments that contain fine grain matrix material<ref name=":5" />.

Different lithologies also respond differently to geological processes. Sandstone reservoirs are among the most common hydrocarbon reservoirs because they can preserve great porosity between sediment grains. Carbonate reservoirs, including limestone and dolostone, often undergo many diagenetic changes through processes such as dissolution, recrystallization, and dolomitization due to their greater chemical reactivity. Rather than relying solely on primary pore space, carbonate reservoirs often develop secondary porosity through diagenesis and fracturing. As a result, both sandstone and carbonate reservoirs often have the capacity to contain hydrocarbons, although having very different pore systems and geological histories<ref name=":5" />.

Following deposition, sediment undergoes diagenesis when physical and chemical changes occur as the sediment is transformed into sedimentary rock. Important stages in reservoir evolution include eodiagenesis (early burial diagenesis), mesodiagenesis (burial diagenesis), and telodiagenesis (uplift-related changes)<ref name=":5" />. During these stages, sediments experience compaction, dissolution, mineral replacement, fracturing, and fluid interactions that can significantly alter reservoir properties. These diagenetic processes can reduce reservoir quality. Compaction during burial decreases pore space as sediment gains become more tightly packed. Chemical compaction and pressure solution may further reduce porosity. Minerals such as quartz, calcite, dolomite, and clay can fill pore spaces and restrict fluid movement. Quartz cementation is identified as one of the most important pore-filling processes in deep buried sandstone reservoirs because of the way it reduces the amount of available pore space progressively. Clay mineral does so similarly and may significantly decrease permeability by blocking pores and restricting fluid flow <ref name=":5">{{Cite journal|last=Worden|first=R. H.|last2=Armitage|first2=P. J.|last3=Butcher|first3=A. R.|last4=Churchill|first4=J. M.|last5=Csoma|first5=A. E.|last6=Hollis|first6=C.|last7=Lander|first7=R. H.|last8=Omma|first8=J. E.|date=2018|title=Petroleum reservoir quality prediction: overview and contrasting approaches from sandstone and carbonate communities|url=https://doi.org/10.1144/SP435.21|journal=Geological Society|volume=435|pages=1-31}}</ref>.

Reservoir quality is not solely determined by burial and porosity. The final characteristics of a reservoir are reflected by the preservation of pore space. Reservoirs with similar depositional origination may exhibit very different porosity and permeability depending on their diagenetic history and the geological conditions they experienced during burial and uplift<ref name=":5" />.
== Oil and Gas Exploration: Seismic Technology ==

Now we know the importance of oil and gas to our society, and how they were formed, the next question is where to locate them. Since reservoirs are below the surface, geologists cannot directly see where they are before drilling. This makes drilling a gamble, and that's where seismic reflection technology contributes to lowering the risk. It works as a tool that helps geologists to create an image of what is beneath the surface before they decide where to drill <ref name=":0">{{Cite journal|last=Mohammed|first=Farfour|date=2016-05-01|title=A review on multicomponent seismology: A potential seismic application for reservoir characterization|url=https://www.sciencedirect.com/science/article/pii/S2090123215001125|journal=Journal of Advanced Research|volume=3|pages=515-524}}</ref>.[[File:Seismic_Survey_and_Mechanism.png|thumb|left|500x500px|Figure 1. Seismic Technology and Mechanism for oil Exploration]]The working principle behind seismic is to use energy waves to explore underground rock layers. During a survey, energy waves are sent into the ground. When waves hit the boundaries between rock layers, some of the energy bounces back to the surface, while some goes further. Receivers then pick up these reflected waves and give information about the depth, shape and arrangement of subsurface layers by analyzing the different waves using the pre-known typical rock’s density and acoustic impedance. After processing, the data can be shown as profiles or 3D seismic images <ref>{{Cite journal|last=Ilya|first=Tsvankin|date=2010-09-01|title=Seismic anisotropy in exploration and reservoir characterization: An overview|url=https://www.researchgate.net/publication/228633261_Seismic_anisotropy_in_exploration_and_reservoir_characterization_An_overview|journal=Geophysics|volume=75}}</ref>.

This is essential because oil and gas need geological structures to build up, and seismic interpretation helps identify these structures. For example, folds show up as layers in seismic images. If the fold creates an anticline, oil and gas might move upward and get trapped near the top. Faults can be spotted when rock layers are broken or displaced. Faults can create traps but might let hydrocarbons escape as well if they aren't sealed properly. So seismic data are not just used to "find oil", they help us understand if subsurface geology has the right structure to store oil and gas<ref>{{Cite journal|last=Lawson|first=M.|date=2018-02-19|title=Geochemical applications in petroleum systems analysis: New constraints and the power of integration|url=https://www.researchgate.net/publication/323282762_Geochemical_applications_in_petroleum_systems_analysis_New_constraints_and_the_power_of_integration|journal=Geological Society, London, Special Publications|volume=468|pages=6}}</ref> . More than locating the reservoir, seismic technology also helps geologists understand its geometry. This includes the shape, thickness, depth and continuity of a reservoir. This matters because a reservoir can be located but not profitable for business. With current technology and the purpose of maximizing the future extraction, geologists are targeting large and continuous reservoirs rather than thin and isolated ones. Seismic data can help pinpoint the drilling target by showing where the reservoir might be thicker or larger<ref name=":0" /> .

An exploration workflow usually starts with a regional study. The first step is for geologists to determine if the region has a petroleum system with possible traps that contain oil. Then there are follow-up seismic surveys to get evidence and more information. Next, geoscientists interpret the data to distinguish geological structures and possible drilling targets. These decisions are assisted by other data, such as core samples. Finally, drilling locations are chosen based on different criteria <ref name=":1">{{Cite journal|last=Ma|first=Yuan Zhe|date=2011-01-01|title=Uncertainty Analysis in Reservoir Characterization and Management: How Much Should We Know About What We Don't Know?|url=https://pubs.geoscienceworld.org/aapg/books/edited-volume/1248/chapter-abstract/107059711/Uncertainty-Analysis-in-Reservoir-Characterization?redirectedFrom=fulltext|journal=AAPG Memoir|volume=1|pages=15}}</ref>.

However, seismic technology is not perfect. As an imaging technique that relies on the reflection of waves, some thin reservoirs or structures can be hard to detect. Also, seismic data cannot directly show the oil and gas but uses structures to infer their existence. Based on this limitation, seismic technology is more like a tool that reduces drilling risk than eliminates all uncertainties <ref>Saad, M. R., & Jadeer, A.-S. (2022). ''Seismic Method for Exploration Oil and Gas Reservoirs''. <nowiki>https://doi.org/10.1007/978-981-99-1964-2_89</nowiki></ref>.

== Oil and Gas Extraction: How Geology Determines Engineering Decisions ==
Once an oil reservoir is proven as continuous and profitable, geology still plays a role in deciding how to extract the resources. In a word, engineering decisions and extraction methods are based on how the subsurface looks and how fluids move through the rock.

Engineers need more geology information before deciding where to drill. They want to know the depth of the potential drilling trajectory, the thickness of the oil reservoir, and the fluid contacts of the reservoir to optimize the performance. For example, a rich oil-bearing zone in the reservoir should be the highest priority to place the well nearby. However, if the zone is disrupted by some faults, then engineers and geologists must determine whether these faults connect to parts of the reservoir or cut it into separate parts. Moreover, if the production well is too close to a water or gas zone, a water or gas breakthrough is likely to happen and reduce oil production. In a real-world case, a breakthrough can easily turn a high-production well into a shut-down.
[[File:Reservori_Simulation_Model.jpg|thumb|Figure 2. The reservoir modeling workflow showing the sequence of stages in data acquisition and interpretation<ref name=":2">Abel, M., Garcia, L., Lorenzatti, A., & De Ros, L. (2010, October 26). ''SEMANTIC INTEROPERABILITY IN THE PETROLEUM CHAIN: THE CONTRIBUTION OF ONTOLOGICAL ANALYSIS''.</ref>|549x549px]]Reservoir simulation is a great tool to use in oil extraction, just like how seismic technology assists oil exploration. A reservoir model is a digital version of a reservoir with a vivid representation of reservoir structures and various relevant properties like pressure, permeability, porosity, and saturation of each phase. Engineers use this model to predict how the reservoir might behave during production. For instance, the model can estimate production rates, pressure changes, and any potential water cut. It can also achieve optimization on certain jobs, like comparing different production plans and well placement strategies. Since the model is built purely based on geological data, its quality varies depending on how well the regional geology is captured and understood, and this can also be a limitation of the reservoir model <ref name=":2" /><ref>Sambo, C., Iferobia, C. C., Babasafari, A. A., Rezaei, S., & Akanni, O. A. (2020). The Role of Time Lapse(4D) Seismic Technology as Reservoir Monitoring and Surveillance Tool: A Comprehensive Review. ''Journal of Natural Gas Science and Engineering'', ''80'', 103312. <nowiki>https://doi.org/10.1016/j.jngse.2020.103312</nowiki></ref>.

Since there are many different types of reservoirs, extraction methods have also been developed differently to achieve efficient production for each case. And they can be separated under two main reservoir types: conventional and unconventional.
{| class="wikitable"
|+
!Reservoir Type
!Geological Characteristics
!Main Extraction Methods
!Engineering
Reason
|-
|Conventional reservoirs
|High permeability and porosity for fluids to flow naturally toward the well through connected pore spaces
|Primary production relies on natural reservoir pressure and secondary recovery methods like water injection are used to maintain the pressure
|Maintain and increase reservoir pressure to improve flow toward production wells
|-
|Unconventional reservoirs
|Low permeability so fluids are trapped in rocks or exist as highly viscous bitumen
|Horizontal drilling and hydraulic fracturing are commonly used for shale gas and tight oil
For deep oil sands, steam-assisted gravity drainage can be used by injecting steam underground to heat bitumen and lower the viscousity
|Create flow pathways to make hydrocarbons mobile enough to be produced
|}
Overall, geology has a strong influence on engineering decisions in oil and gas extraction. Geology informs engineers to know the reservoir quality, what extraction methodology can be applied, and what risks might exist during production. Geological information has also been integrated into reservoir models to provide a more in-depth understanding and optimization. Oil extraction is not just about improving equipment and technology, it is also a process in which geological knowledge is applied with engineering decisions.

== Chemical Engineering and Petroleum Products ==
[[File:Fractional Distillation.jpg|thumb|Fractional Distillation Process of Crude Oil (Wigmore Trading, n.d.)|512x512px]]
Crude oil, in its unrefined state, has almost no direct utility due to its highly complex molecular constitution. It exists fundamentally as a dense, complex mixture of hundreds of different hydrocarbons. The three basic components of crude oil are alkanes, cycloalkanes, and aromatics. The primary steps of chemical engineering within petroleum refineries are physical separation and chemical conversion. The first step separates the heterogeneous mixture into narrower, manageable fractions based on physical properties, and the second step upgrades these fractions into high-value, commercially viable products. This transformation from raw, unusable crude oil into high-value fuels relies on a sequence of thermal processes and complex catalytic reactions that manipulate molecular structures. (Sani et al., 2024)

The foundational stage of any refinery configuration is fractional distillation. It depends on the differential volatility and boiling points of the constituent hydrocarbons within crude oil. The process is commonly operationalized through the Atmospheric Distillation Unit: crude oil is preheated to approximately 350-400°C and pumped into the lowest and hottest level in the Fractional distillation tower. As the vaporized oil ascends through a series of distillation trays with temperature decreasing, it cools progressively. Hydrocarbons with lower boiling points condense at higher levels of the tower. This allows the continuous withdrawal of light fractions such as liquefied petroleum gas, naphtha, kerosene, and gas oil. (Sani et al., 2024)

Since the initial fractions obtained from atmospheric distillation are mostly the result of physical separation, they can't break the products into smaller molecules. Those distilled heavy molecules are hardly suitable for the commercial market. Thus, refineries rely heavily on cracking processes to convert these high-molecular-weight hydrocarbons into higher-value, lighter liquid fuels. This process involves the thermal or catalytic breaking of carbon-carbon covalent bonds in long-chain alkanes. Modern chemical engineering uses Fluid Catalytic Cracking (FCC) as the primary process. The market prefers this method due to its ability to maximize high-value gasoline yields from heavy gas oils. The efficiency of FCC is highly influenced by the use of highly active, acidic zeolite catalysts. Zeolite selectively accelerates secondary hydrocarbon cracking while minimizing unwanted coke formation. Alternatively, for middle distillates such as jet fuel and diesel, hydrocracking is used. This process takes place in a high-temperature, high-pressure, hydrogen-rich environment. Over catalysts, the hydrogen saturates aromatic rings and breaks the carbon chains. (Sani et al., 2024)

Reforming is another chemical process that changes a molecule's structure without altering the overall number of carbon atoms. This method is mainly used for straight-run naphtha, a distillation product. Straight-run naphtha has a suitable molecular size for vehicle engines, but the straight-chain alkanes it contains can cause knocking. Reforming uses chemical reactions to trigger isomerization, cyclization or dehydration of the straight chains. During catalytic reforming, a large amount of hydrogen is formed as a byproduct of dehydrogenation. This is great in the engineering industry, since hydrogen can be pumped straight to hydrotreating. Hydrotreating is a process for purifying. Crude oil naturally contains heteroatom impurities like sulphur, nitrogen, and heavy metals. With the purification process, SOx and NOx won't be released during burning, thereby preventing catalyst poisoning. Under high pressure and temperature, hydrogen can convert sulphur and nitrogen into H2S and NH3, separating the impurities completely. (Sani et al., 2024)

Through the physical separations and chemical alterations described above, crude oil ultimately becomes market products and plays an important role in the global economy. These outputs are broadly divided into three categories: transportation fuels, industrial specialty products, and petrochemical feedstocks. Transportation fuels such as gasoline, diesel, and kerosene sustain global logistics and transportation networks daily. They determine whether the international trade markets can function efficiently. Industrial specialty products like asphalt, which is extracted from heavy residues, play an indispensable role as the structural binder in global infrastructure development. Nevertheless, according to Levi et al. (2018), straight-run naphtha, serving as a petrochemical feedstock, has been a source for the global chemical industry. Through steam cracking, primary light olefins and aromatics are synthesized. Thus, downstream polymerization can convert them into ubiquitous materials such as polyethylene, polypropylene, and synthetic rubbers. (Levi et al., 2018)

== Environmental issues ==
[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Conclusion / Your Evaluation of the Connections==

=== Conclusion: ===

=== Breakdown of group contributions: ===
Marijke:

* Introduction to Petroleum Systems
* Geological Formation
* Reservoir Quality

Jack:

* Oil and Gas Exploration: Seismic Technology
* Oil and Gas Extraction: How Geology Determines Engineering Decisions
Keming:
* Chemical Engineering and Petroleum Products
* Environmental Issues

=== AI Statement: ===
AI tools were used to support brainstorming ideas and to delegate portions within the group. AI-generated images are used and cited. All final written content have been created and reviewed by all group members.

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-17T16:16:36Z

KemingWu: /* Breakdown of group contributions: */

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-17T16:16:20Z

KemingWu: /* Conclusion / Your Evaluation of the Connections */

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-17T16:12:50Z

KemingWu: /* Chemical Engineering and Petroleum Products */

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-17T03:15:42Z

KemingWu: /* Chemical Engineering and Petroleum Products */

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-17T02:50:30Z

KemingWu: /* Chemical Engineering and Petroleum Products */

Add Summary Here

==Statement of connection and why you chose it==

==Main text==

=== Oil and Gas Exploration: Seismic Technology ===
Now we know the importance of oil and gas to our society, and how they were formed, the next question is where to locate them. Since reservoirs are below the surface, geologists cannot directly see where they are before drilling. This makes drilling a gamble, and that's where seismic reflection technology contributes to lowering the risk. It works as a tool that helps geologists to create an image of what is beneath the surface before they decide where to drill <ref name=":0">{{Cite journal|last=Mohammed|first=Farfour|date=2016-05-01|title=A review on multicomponent seismology: A potential seismic application for reservoir characterization|url=https://www.sciencedirect.com/science/article/pii/S2090123215001125|journal=Journal of Advanced Research|volume=3|pages=515-524}}</ref>.[[File:Seismic_Survey_and_Mechanism.png|thumb|left|500x500px|Figure 1. Seismic Technology and Mechanism for oil Exploration]]The working principle behind seismic is to use energy waves to explore underground rock layers. During a survey, energy waves are sent into the ground. When waves hit the boundaries between rock layers, some of the energy bounces back to the surface, while some goes further. Receivers then pick up these reflected waves and give information about the depth, shape and arrangement of subsurface layers by analyzing the different waves using the pre-known typical rock’s density and acoustic impedance. After processing, the data can be shown as profiles or 3D seismic images <ref>{{Cite journal|last=Ilya|first=Tsvankin|date=2010-09-01|title=Seismic anisotropy in exploration and reservoir characterization: An overview|url=https://www.researchgate.net/publication/228633261_Seismic_anisotropy_in_exploration_and_reservoir_characterization_An_overview|journal=Geophysics|volume=75}}</ref>.

This is essential because oil and gas need geological structures to build up, and seismic interpretation helps identify these structures. For example, folds show up as layers in seismic images. If the fold creates an anticline, oil and gas might move upward and get trapped near the top. Faults can be spotted when rock layers are broken or displaced. Faults can create traps but might let hydrocarbons escape as well if they aren't sealed properly. So seismic data are not just used to "find oil", they help us understand if subsurface geology has the right structure to store oil and gas<ref>{{Cite journal|last=Lawson|first=M.|date=2018-02-19|title=Geochemical applications in petroleum systems analysis: New constraints and the power of integration|url=https://www.researchgate.net/publication/323282762_Geochemical_applications_in_petroleum_systems_analysis_New_constraints_and_the_power_of_integration|journal=Geological Society, London, Special Publications|volume=468|pages=6}}</ref> . More than locating the reservoir, seismic technology also helps geologists understand its geometry. This includes the shape, thickness, depth and continuity of a reservoir. This matters because a reservoir can be located but not profitable for business. With current technology and the purpose of maximizing the future extraction, geologists are targeting large and continuous reservoirs rather than thin and isolated ones. Seismic data can help pinpoint the drilling target by showing where the reservoir might be thicker or larger<ref name=":0" /> .

An exploration workflow usually starts with a regional study. The first step is for geologists to determine if the region has a petroleum system with possible traps that contain oil. Then there are follow-up seismic surveys to get evidence and more information. Next, geoscientists interpret the data to distinguish geological structures and possible drilling targets. These decisions are assisted by other data, such as core samples. Finally, drilling locations are chosen based on different criteria <ref name=":1">{{Cite journal|last=Ma|first=Yuan Zhe|date=2011-01-01|title=Uncertainty Analysis in Reservoir Characterization and Management: How Much Should We Know About What We Don't Know?|url=https://pubs.geoscienceworld.org/aapg/books/edited-volume/1248/chapter-abstract/107059711/Uncertainty-Analysis-in-Reservoir-Characterization?redirectedFrom=fulltext|journal=AAPG Memoir|volume=1|pages=15}}</ref>.

However, seismic technology is not perfect. As an imaging technique that relies on the reflection of waves, some thin reservoirs or structures can be hard to detect. Also, seismic data cannot directly show the oil and gas but uses structures to infer their existence. Based on this limitation, seismic technology is more like a tool that reduces drilling risk than eliminates all uncertainties <ref>Saad, M. R., & Jadeer, A.-S. (2022). ''Seismic Method for Exploration Oil and Gas Reservoirs''. <nowiki>https://doi.org/10.1007/978-981-99-1964-2_89</nowiki></ref>.

=== Oil and Gas Extraction: How Geology Determines Engineering Decisions ===
Once an oil reservoir is proven as continuous and profitable, geology still plays a role in deciding how to extract the resources. In a word, engineering decisions and extraction methods are based on how the subsurface looks and how fluids move through the rock.

One of the important links between geology and engineering is reservoir quality, which mainly depends on porosity and permeability. Porosity is a measurement of how much open space exists inside the rock. This will decide how much oil, gas and water the rock can hold. Permeability refers to the connectivity of those pore spaces, deciding how easily fluids can flow between the rocks. A reservoir with high porosity can still be unproducible if those pores are not connected, so oil and gas cannot have a valid pathway to flow toward the production well. So, a high-quality reservoir needs rocks to have the ability to both store hydrocarbons and produce them <ref name=":1" />.

Engineers still need more geology information before deciding where to drill. They want to know the depth of the potential drilling trajectory, the thickness of the oil reservoir, and the fluid contacts of the reservoir to optimize the performance. For example, a rich oil-bearing zone in the reservoir should be the highest priority to place the well nearby. However, if the zone is disrupted by some faults, then engineers and geologists must determine whether these faults connect to parts of the reservoir or cut it into separate parts. Moreover, if the production well is too close to a water or gas zone, a water or gas breakthrough is likely to happen and reduce oil production. In a real-world case, a breakthrough can easily turn a high-production well into a shut-down.
[[File:Reservori_Simulation_Model.jpg|thumb|Figure 2. The reservoir modeling workflow showing the sequence of stages in data acquisition and interpretation<ref name=":2">Abel, M., Garcia, L., Lorenzatti, A., & De Ros, L. (2010, October 26). ''SEMANTIC INTEROPERABILITY IN THE PETROLEUM CHAIN: THE CONTRIBUTION OF ONTOLOGICAL ANALYSIS''.</ref>|549x549px]]

Reservoir simulation is a great tool to use in oil extraction, just like how seismic technology assists oil exploration. A reservoir model is a digital version of a reservoir with a vivid representation of reservoir structures and various relevant properties like pressure, permeability, porosity, and saturation of each phase. Engineers use this model to predict how the reservoir might behave during production. For instance, the model can estimate production rates, pressure changes, and any potential water cut. It can also achieve optimization on certain jobs, like comparing different production plans and well placement strategies. Since the model is built purely based on geological data, its quality varies depending on how well the regional geology is captured and understood, and this can also be a limitation of the reservoir model <ref name=":2" /><ref>Sambo, C., Iferobia, C. C., Babasafari, A. A., Rezaei, S., & Akanni, O. A. (2020). The Role of Time Lapse(4D) Seismic Technology as Reservoir Monitoring and Surveillance Tool: A Comprehensive Review. ''Journal of Natural Gas Science and Engineering'', ''80'', 103312. <nowiki>https://doi.org/10.1016/j.jngse.2020.103312</nowiki></ref>.

Since there are many different types of reservoirs, extraction methods have also been developed differently to achieve efficient production for each case. And they can be separated under two main reservoir types: conventional and unconventional.
{| class="wikitable"
|+
!Reservoir Type
!Geological Characteristics
!Main Extraction Methods
!Engineering
Reason
|-
|Conventional reservoirs
|High permeability and porosity for fluids to flow naturally toward the well through connected pore spaces
|Primary production relies on natural reservoir pressure and secondary recovery methods like water injection are used to maintain the pressure
|Maintain and increase reservoir pressure to improve flow toward production wells
|-
|Unconventional reservoirs
|Low permeability so fluids are trapped in rocks or exist as highly viscous bitumen
|Horizontal drilling and hydraulic fracturing are commonly used for shale gas and tight oil
For deep oil sands, steam-assisted gravity drainage can be used by injecting steam underground to heat bitumen and lower the viscousity
|Create flow pathways to make hydrocarbons mobile enough to be produced
|}
Overall, geology has a strong influence on engineering decisions in oil and gas extraction. Geology informs engineers to know the reservoir quality, what extraction methodology can be applied, and what risks might exist during production. Geological information has also been integrated into reservoir models to provide a more in-depth understanding and optimization. Oil extraction is not just about improving equipment and technology, it is also a process in which geological knowledge is applied with engineering decisions.

=== Chemical Engineering and Petroleum Products ===
[[File:Fractional Distillation.jpg|thumb|Fractional Distillation Process of Crude Oil (Wigmore Trading, n.d.)|512x512px]]
Crude oil, in its unrefined state, has almost no direct utility due to its highly complex molecular constitution. It exists fundamentally as a dense, complex mixture of hundreds of different hydrocarbons. The three basic components of crude oil are alkanes, cycloalkanes, and aromatics. The primary steps of chemical engineering within petroleum refineries are physical separation and chemical conversion. The first step separates the heterogeneous mixture into narrower, manageable fractions based on physical properties, and the second step upgrades these fractions into high-value, commercially viable products. This transformation from raw, unusable crude oil into high-value fuels relies on a sequence of thermal processes and complex catalytic reactions that manipulate molecular structures. (Sani et al., 2024)

The foundational stage of any refinery configuration is fractional distillation. It depends on the differential volatility and boiling points of the constituent hydrocarbons within crude oil. The process is commonly operationalized through the Atmospheric Distillation Unit: crude oil is preheated to approximately 350-400°C and pumped into the lowest and hottest level in the Fractional distillation tower. As the vaporized oil ascends through a series of distillation trays with temperature decreasing, it cools progressively. Hydrocarbons with lower boiling points condense at higher levels of the tower. This allows the continuous withdrawal of light fractions such as liquefied petroleum gas, naphtha, kerosene, and gas oil. (Sani et al., 2024)

Since the initial fractions obtained from atmospheric distillation are mostly the result of physical separation, they can't break the products into smaller molecules. Those distilled heavy molecules are hardly suitable for the commercial market. Thus, refineries rely heavily on cracking processes to convert these high-molecular-weight hydrocarbons into higher-value, lighter liquid fuels. This process involves the thermal or catalytic breaking of carbon-carbon covalent bonds in long-chain alkanes. Modern chemical engineering uses Fluid Catalytic Cracking (FCC) as the primary process. The market prefers this method due to its ability to maximize high-value gasoline yields from heavy gas oils. The efficiency of FCC is highly influenced by the use of highly active, acidic zeolite catalysts. Zeolite selectively accelerates secondary hydrocarbon cracking while minimizing unwanted coke formation. Alternatively, for middle distillates such as jet fuel and diesel, hydrocracking is used. This process takes place in a high-temperature, high-pressure, hydrogen-rich environment. Over catalysts, the hydrogen saturates aromatic rings and breaks the carbon chains. (Sani et al., 2024)

Reforming is another chemical process that changes a molecule's structure without altering the overall number of carbon atoms. This method is mainly used for straight-run naphtha, a distillation product. Straight-run naphtha has a suitable molecular size for vehicle engines, but the straight-chain alkanes it contains can cause knocking. Reforming uses chemical reactions to trigger isomerization, cyclization or dehydration of the straight chains. During catalytic reforming, a large amount of hydrogen is formed as a byproduct of dehydrogenation. This is great in the engineering industry, since hydrogen can be pumped straight to hydrotreating.

(Sani et al., 2024)

=== Environmental issues ===
[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Conclusion / Your Evaluation of the Connections==

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-17T02:42:24Z

KemingWu: /* Chemical Engineering and Petroleum Products */

Add Summary Here

==Statement of connection and why you chose it==

==Main text==

=== Oil and Gas Exploration: Seismic Technology ===
Now we know the importance of oil and gas to our society, and how they were formed, the next question is where to locate them. Since reservoirs are below the surface, geologists cannot directly see where they are before drilling. This makes drilling a gamble, and that's where seismic reflection technology contributes to lowering the risk. It works as a tool that helps geologists to create an image of what is beneath the surface before they decide where to drill <ref name=":0">{{Cite journal|last=Mohammed|first=Farfour|date=2016-05-01|title=A review on multicomponent seismology: A potential seismic application for reservoir characterization|url=https://www.sciencedirect.com/science/article/pii/S2090123215001125|journal=Journal of Advanced Research|volume=3|pages=515-524}}</ref>.[[File:Seismic_Survey_and_Mechanism.png|thumb|left|500x500px|Figure 1. Seismic Technology and Mechanism for oil Exploration]]The working principle behind seismic is to use energy waves to explore underground rock layers. During a survey, energy waves are sent into the ground. When waves hit the boundaries between rock layers, some of the energy bounces back to the surface, while some goes further. Receivers then pick up these reflected waves and give information about the depth, shape and arrangement of subsurface layers by analyzing the different waves using the pre-known typical rock’s density and acoustic impedance. After processing, the data can be shown as profiles or 3D seismic images <ref>{{Cite journal|last=Ilya|first=Tsvankin|date=2010-09-01|title=Seismic anisotropy in exploration and reservoir characterization: An overview|url=https://www.researchgate.net/publication/228633261_Seismic_anisotropy_in_exploration_and_reservoir_characterization_An_overview|journal=Geophysics|volume=75}}</ref>.

This is essential because oil and gas need geological structures to build up, and seismic interpretation helps identify these structures. For example, folds show up as layers in seismic images. If the fold creates an anticline, oil and gas might move upward and get trapped near the top. Faults can be spotted when rock layers are broken or displaced. Faults can create traps but might let hydrocarbons escape as well if they aren't sealed properly. So seismic data are not just used to "find oil", they help us understand if subsurface geology has the right structure to store oil and gas<ref>{{Cite journal|last=Lawson|first=M.|date=2018-02-19|title=Geochemical applications in petroleum systems analysis: New constraints and the power of integration|url=https://www.researchgate.net/publication/323282762_Geochemical_applications_in_petroleum_systems_analysis_New_constraints_and_the_power_of_integration|journal=Geological Society, London, Special Publications|volume=468|pages=6}}</ref> . More than locating the reservoir, seismic technology also helps geologists understand its geometry. This includes the shape, thickness, depth and continuity of a reservoir. This matters because a reservoir can be located but not profitable for business. With current technology and the purpose of maximizing the future extraction, geologists are targeting large and continuous reservoirs rather than thin and isolated ones. Seismic data can help pinpoint the drilling target by showing where the reservoir might be thicker or larger<ref name=":0" /> .

An exploration workflow usually starts with a regional study. The first step is for geologists to determine if the region has a petroleum system with possible traps that contain oil. Then there are follow-up seismic surveys to get evidence and more information. Next, geoscientists interpret the data to distinguish geological structures and possible drilling targets. These decisions are assisted by other data, such as core samples. Finally, drilling locations are chosen based on different criteria <ref name=":1">{{Cite journal|last=Ma|first=Yuan Zhe|date=2011-01-01|title=Uncertainty Analysis in Reservoir Characterization and Management: How Much Should We Know About What We Don't Know?|url=https://pubs.geoscienceworld.org/aapg/books/edited-volume/1248/chapter-abstract/107059711/Uncertainty-Analysis-in-Reservoir-Characterization?redirectedFrom=fulltext|journal=AAPG Memoir|volume=1|pages=15}}</ref>.

However, seismic technology is not perfect. As an imaging technique that relies on the reflection of waves, some thin reservoirs or structures can be hard to detect. Also, seismic data cannot directly show the oil and gas but uses structures to infer their existence. Based on this limitation, seismic technology is more like a tool that reduces drilling risk than eliminates all uncertainties <ref>Saad, M. R., & Jadeer, A.-S. (2022). ''Seismic Method for Exploration Oil and Gas Reservoirs''. <nowiki>https://doi.org/10.1007/978-981-99-1964-2_89</nowiki></ref>.

=== Oil and Gas Extraction: How Geology Determines Engineering Decisions ===
Once an oil reservoir is proven as continuous and profitable, geology still plays a role in deciding how to extract the resources. In a word, engineering decisions and extraction methods are based on how the subsurface looks and how fluids move through the rock.

One of the important links between geology and engineering is reservoir quality, which mainly depends on porosity and permeability. Porosity is a measurement of how much open space exists inside the rock. This will decide how much oil, gas and water the rock can hold. Permeability refers to the connectivity of those pore spaces, deciding how easily fluids can flow between the rocks. A reservoir with high porosity can still be unproducible if those pores are not connected, so oil and gas cannot have a valid pathway to flow toward the production well. So, a high-quality reservoir needs rocks to have the ability to both store hydrocarbons and produce them <ref name=":1" />.

Engineers still need more geology information before deciding where to drill. They want to know the depth of the potential drilling trajectory, the thickness of the oil reservoir, and the fluid contacts of the reservoir to optimize the performance. For example, a rich oil-bearing zone in the reservoir should be the highest priority to place the well nearby. However, if the zone is disrupted by some faults, then engineers and geologists must determine whether these faults connect to parts of the reservoir or cut it into separate parts. Moreover, if the production well is too close to a water or gas zone, a water or gas breakthrough is likely to happen and reduce oil production. In a real-world case, a breakthrough can easily turn a high-production well into a shut-down.
[[File:Reservori_Simulation_Model.jpg|thumb|Figure 2. The reservoir modeling workflow showing the sequence of stages in data acquisition and interpretation<ref name=":2">Abel, M., Garcia, L., Lorenzatti, A., & De Ros, L. (2010, October 26). ''SEMANTIC INTEROPERABILITY IN THE PETROLEUM CHAIN: THE CONTRIBUTION OF ONTOLOGICAL ANALYSIS''.</ref>|549x549px]]

Reservoir simulation is a great tool to use in oil extraction, just like how seismic technology assists oil exploration. A reservoir model is a digital version of a reservoir with a vivid representation of reservoir structures and various relevant properties like pressure, permeability, porosity, and saturation of each phase. Engineers use this model to predict how the reservoir might behave during production. For instance, the model can estimate production rates, pressure changes, and any potential water cut. It can also achieve optimization on certain jobs, like comparing different production plans and well placement strategies. Since the model is built purely based on geological data, its quality varies depending on how well the regional geology is captured and understood, and this can also be a limitation of the reservoir model <ref name=":2" /><ref>Sambo, C., Iferobia, C. C., Babasafari, A. A., Rezaei, S., & Akanni, O. A. (2020). The Role of Time Lapse(4D) Seismic Technology as Reservoir Monitoring and Surveillance Tool: A Comprehensive Review. ''Journal of Natural Gas Science and Engineering'', ''80'', 103312. <nowiki>https://doi.org/10.1016/j.jngse.2020.103312</nowiki></ref>.

Since there are many different types of reservoirs, extraction methods have also been developed differently to achieve efficient production for each case. And they can be separated under two main reservoir types: conventional and unconventional.
{| class="wikitable"
|+
!Reservoir Type
!Geological Characteristics
!Main Extraction Methods
!Engineering
Reason
|-
|Conventional reservoirs
|High permeability and porosity for fluids to flow naturally toward the well through connected pore spaces
|Primary production relies on natural reservoir pressure and secondary recovery methods like water injection are used to maintain the pressure
|Maintain and increase reservoir pressure to improve flow toward production wells
|-
|Unconventional reservoirs
|Low permeability so fluids are trapped in rocks or exist as highly viscous bitumen
|Horizontal drilling and hydraulic fracturing are commonly used for shale gas and tight oil
For deep oil sands, steam-assisted gravity drainage can be used by injecting steam underground to heat bitumen and lower the viscousity
|Create flow pathways to make hydrocarbons mobile enough to be produced
|}
Overall, geology has a strong influence on engineering decisions in oil and gas extraction. Geology informs engineers to know the reservoir quality, what extraction methodology can be applied, and what risks might exist during production. Geological information has also been integrated into reservoir models to provide a more in-depth understanding and optimization. Oil extraction is not just about improving equipment and technology, it is also a process in which geological knowledge is applied with engineering decisions.

=== Chemical Engineering and Petroleum Products ===
[[File:Fractional Distillation.jpg|thumb|Fractional Distillation Process of Crude Oil (Wigmore Trading, n.d.)|512x512px]]
Crude oil, in its unrefined state, has almost no direct utility due to its highly complex molecular constitution. It exists fundamentally as a dense, complex mixture of hundreds of different hydrocarbons. The three basic components of crude oil are alkanes, cycloalkanes, and aromatics. The primary steps of chemical engineering within petroleum refineries are physical separation and chemical conversion. The first step separates the heterogeneous mixture into narrower, manageable fractions based on physical properties, and the second step upgrades these fractions into high-value, commercially viable products. This transformation from raw, unusable crude oil into high-value fuels relies on a sequence of thermal processes and complex catalytic reactions that manipulate molecular structures. (Sani et al., 2024)

The foundational stage of any refinery configuration is fractional distillation. It depends on the differential volatility and boiling points of the constituent hydrocarbons within crude oil. The process is commonly operationalized through the Atmospheric Distillation Unit: crude oil is preheated to approximately 350-400°C and pumped into the lowest and hottest level in the Fractional distillation tower. As the vaporized oil ascends through a series of distillation trays with temperature decreasing, it cools progressively. Hydrocarbons with lower boiling points condense at higher levels of the tower. This allows the continuous withdrawal of light fractions such as liquefied petroleum gas, naphtha, kerosene, and gas oil. (Sani et al., 2024)

Since the initial fractions obtained from atmospheric distillation are mostly the result of physical separation, they can't break the products into smaller molecules. Those distilled heavy molecules are hardly suitable for the commercial market. Thus, refineries rely heavily on cracking processes to convert these high-molecular-weight hydrocarbons into higher-value, lighter liquid fuels. This process involves the thermal or catalytic breaking of carbon-carbon covalent bonds in long-chain alkanes. Modern chemical engineering uses Fluid Catalytic Cracking (FCC) as the primary process. The market prefers this method due to its ability to maximize high-value gasoline yields from heavy gas oils. The efficiency of FCC is highly influenced by the use of highly active, acidic zeolite catalysts. Zeolite selectively accelerates secondary hydrocarbon cracking while minimizing unwanted coke formation. Alternatively, for middle distillates such as jet fuel and diesel, hydrocracking is used. This process takes place in a high-temperature, high-pressure, hydrogen-rich environment. Over catalysts, the hydrogen saturates aromatic rings and breaks the carbon chains. (Sani et al., 2024)

Reforming is another chemical process that changes a molecule's structure without altering the overall number of carbon atoms. This method is mainly used for straight-run naphtha, a distillation product. Straight-run naphtha has a suitable molecular size for vehicle engines, but the straight-chain alkanes it contains can cause knocking. Reforming uses chemical reactions to trigger isomerization, cyclization or dehydration of the straight chains. During catalytic reforming, a large amount of hydrogen is formed as a byproduct of dehydrogenation. This is great in the engineering industry, since the hydrogen can be pumped straight to work for hydrotreating.

=== Environmental issues ===
[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Conclusion / Your Evaluation of the Connections==

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-17T01:29:41Z

KemingWu: /* Chemical Engineering and Petroleum Products */

Add Summary Here

==Statement of connection and why you chose it==

==Main text==

=== Oil and Gas Exploration: Seismic Technology ===
Now we know the importance of oil and gas to our society, and how they were formed, the next question is where to locate them. Since reservoirs are below the surface, geologists cannot directly see where they are before drilling. This makes drilling a gamble, and that's where seismic reflection technology contributes to lowering the risk. It works as a tool that helps geologists to create an image of what is beneath the surface before they decide where to drill <ref name=":0">{{Cite journal|last=Mohammed|first=Farfour|date=2016-05-01|title=A review on multicomponent seismology: A potential seismic application for reservoir characterization|url=https://www.sciencedirect.com/science/article/pii/S2090123215001125|journal=Journal of Advanced Research|volume=3|pages=515-524}}</ref>.[[File:Seismic_Survey_and_Mechanism.png|thumb|left|500x500px|Figure 1. Seismic Technology and Mechanism for oil Exploration]]The working principle behind seismic is to use energy waves to explore underground rock layers. During a survey, energy waves are sent into the ground. When waves hit the boundaries between rock layers, some of the energy bounces back to the surface, while some goes further. Receivers then pick up these reflected waves and give information about the depth, shape and arrangement of subsurface layers by analyzing the different waves using the pre-known typical rock’s density and acoustic impedance. After processing, the data can be shown as profiles or 3D seismic images <ref>{{Cite journal|last=Ilya|first=Tsvankin|date=2010-09-01|title=Seismic anisotropy in exploration and reservoir characterization: An overview|url=https://www.researchgate.net/publication/228633261_Seismic_anisotropy_in_exploration_and_reservoir_characterization_An_overview|journal=Geophysics|volume=75}}</ref>.

This is essential because oil and gas need geological structures to build up, and seismic interpretation helps identify these structures. For example, folds show up as layers in seismic images. If the fold creates an anticline, oil and gas might move upward and get trapped near the top. Faults can be spotted when rock layers are broken or displaced. Faults can create traps but might let hydrocarbons escape as well if they aren't sealed properly. So seismic data are not just used to "find oil", they help us understand if subsurface geology has the right structure to store oil and gas<ref>{{Cite journal|last=Lawson|first=M.|date=2018-02-19|title=Geochemical applications in petroleum systems analysis: New constraints and the power of integration|url=https://www.researchgate.net/publication/323282762_Geochemical_applications_in_petroleum_systems_analysis_New_constraints_and_the_power_of_integration|journal=Geological Society, London, Special Publications|volume=468|pages=6}}</ref> . More than locating the reservoir, seismic technology also helps geologists understand its geometry. This includes the shape, thickness, depth and continuity of a reservoir. This matters because a reservoir can be located but not profitable for business. With current technology and the purpose of maximizing the future extraction, geologists are targeting large and continuous reservoirs rather than thin and isolated ones. Seismic data can help pinpoint the drilling target by showing where the reservoir might be thicker or larger<ref name=":0" /> .

An exploration workflow usually starts with a regional study. The first step is for geologists to determine if the region has a petroleum system with possible traps that contain oil. Then there are follow-up seismic surveys to get evidence and more information. Next, geoscientists interpret the data to distinguish geological structures and possible drilling targets. These decisions are assisted by other data, such as core samples. Finally, drilling locations are chosen based on different criteria <ref name=":1">{{Cite journal|last=Ma|first=Yuan Zhe|date=2011-01-01|title=Uncertainty Analysis in Reservoir Characterization and Management: How Much Should We Know About What We Don't Know?|url=https://pubs.geoscienceworld.org/aapg/books/edited-volume/1248/chapter-abstract/107059711/Uncertainty-Analysis-in-Reservoir-Characterization?redirectedFrom=fulltext|journal=AAPG Memoir|volume=1|pages=15}}</ref>.

However, seismic technology is not perfect. As an imaging technique that relies on the reflection of waves, some thin reservoirs or structures can be hard to detect. Also, seismic data cannot directly show the oil and gas but uses structures to infer their existence. Based on this limitation, seismic technology is more like a tool that reduces drilling risk than eliminates all uncertainties <ref>Saad, M. R., & Jadeer, A.-S. (2022). ''Seismic Method for Exploration Oil and Gas Reservoirs''. <nowiki>https://doi.org/10.1007/978-981-99-1964-2_89</nowiki></ref>.

=== Oil and Gas Extraction: How Geology Determines Engineering Decisions ===
Once an oil reservoir is proven as continuous and profitable, geology still plays a role in deciding how to extract the resources. In a word, engineering decisions and extraction methods are based on how the subsurface looks and how fluids move through the rock.

One of the important links between geology and engineering is reservoir quality, which mainly depends on porosity and permeability. Porosity is a measurement of how much open space exists inside the rock. This will decide how much oil, gas and water the rock can hold. Permeability refers to the connectivity of those pore spaces, deciding how easily fluids can flow between the rocks. A reservoir with high porosity can still be unproducible if those pores are not connected, so oil and gas cannot have a valid pathway to flow toward the production well. So, a high-quality reservoir needs rocks to have the ability to both store hydrocarbons and produce them <ref name=":1" />.

Engineers still need more geology information before deciding where to drill. They want to know the depth of the potential drilling trajectory, the thickness of the oil reservoir, and the fluid contacts of the reservoir to optimize the performance. For example, a rich oil-bearing zone in the reservoir should be the highest priority to place the well nearby. However, if the zone is disrupted by some faults, then engineers and geologists must determine whether these faults connect to parts of the reservoir or cut it into separate parts. Moreover, if the production well is too close to a water or gas zone, a water or gas breakthrough is likely to happen and reduce oil production. In a real-world case, a breakthrough can easily turn a high-production well into a shut-down.
[[File:Reservori_Simulation_Model.jpg|thumb|Figure 2. The reservoir modeling workflow showing the sequence of stages in data acquisition and interpretation<ref name=":2">Abel, M., Garcia, L., Lorenzatti, A., & De Ros, L. (2010, October 26). ''SEMANTIC INTEROPERABILITY IN THE PETROLEUM CHAIN: THE CONTRIBUTION OF ONTOLOGICAL ANALYSIS''.</ref>|549x549px]]

Reservoir simulation is a great tool to use in oil extraction, just like how seismic technology assists oil exploration. A reservoir model is a digital version of a reservoir with a vivid representation of reservoir structures and various relevant properties like pressure, permeability, porosity, and saturation of each phase. Engineers use this model to predict how the reservoir might behave during production. For instance, the model can estimate production rates, pressure changes, and any potential water cut. It can also achieve optimization on certain jobs, like comparing different production plans and well placement strategies. Since the model is built purely based on geological data, its quality varies depending on how well the regional geology is captured and understood, and this can also be a limitation of the reservoir model <ref name=":2" /><ref>Sambo, C., Iferobia, C. C., Babasafari, A. A., Rezaei, S., & Akanni, O. A. (2020). The Role of Time Lapse(4D) Seismic Technology as Reservoir Monitoring and Surveillance Tool: A Comprehensive Review. ''Journal of Natural Gas Science and Engineering'', ''80'', 103312. <nowiki>https://doi.org/10.1016/j.jngse.2020.103312</nowiki></ref>.

Since there are many different types of reservoirs, extraction methods have also been developed differently to achieve efficient production for each case. And they can be separated under two main reservoir types: conventional and unconventional.
{| class="wikitable"
|+
!Reservoir Type
!Geological Characteristics
!Main Extraction Methods
!Engineering
Reason
|-
|Conventional reservoirs
|High permeability and porosity for fluids to flow naturally toward the well through connected pore spaces
|Primary production relies on natural reservoir pressure and secondary recovery methods like water injection are used to maintain the pressure
|Maintain and increase reservoir pressure to improve flow toward production wells
|-
|Unconventional reservoirs
|Low permeability so fluids are trapped in rocks or exist as highly viscous bitumen
|Horizontal drilling and hydraulic fracturing are commonly used for shale gas and tight oil
For deep oil sands, steam-assisted gravity drainage can be used by injecting steam underground to heat bitumen and lower the viscousity
|Create flow pathways to make hydrocarbons mobile enough to be produced
|}
Overall, geology has a strong influence on engineering decisions in oil and gas extraction. Geology informs engineers to know the reservoir quality, what extraction methodology can be applied, and what risks might exist during production. Geological information has also been integrated into reservoir models to provide a more in-depth understanding and optimization. Oil extraction is not just about improving equipment and technology, it is also a process in which geological knowledge is applied with engineering decisions.

=== Chemical Engineering and Petroleum Products ===
[[File:Fractional Distillation.jpg|thumb|Fractional Distillation Process of Crude Oil (Wigmore Trading, n.d.)|512x512px]]
Crude oil, in its unrefined state, has almost no direct utility due to its highly complex molecular constitution. It exists fundamentally as a dense, complex mixture of hundreds of different hydrocarbons. The three basic components of crude oil are alkanes, cycloalkanes, and aromatics. The primary steps of chemical engineering within petroleum refineries are physical separation and chemical conversion. The first step separates the heterogeneous mixture into narrower, manageable fractions based on physical properties, and the second step upgrades these fractions into high-value, commercially viable products. This transformation from raw, unusable crude oil into high-value fuels relies on a sequence of thermal processes and complex catalytic reactions that manipulate molecular structures. (Sani et al., 2024)

The foundational stage of any refinery configuration is fractional distillation. It depends on the differential volatility and boiling points of the constituent hydrocarbons within crude oil. The process is commonly operationalized through the Atmospheric Distillation Unit: crude oil is preheated to approximately 350-400°C and pumped into the lowest and hottest level in the Fractional distillation tower. As the vaporized oil ascends through a series of distillation trays with temperature decreasing, it cools progressively. Hydrocarbons with lower boiling points condense at higher levels of the tower. This allows the continuous withdrawal of light fractions such as liquefied petroleum gas, naphtha, kerosene, and gas oil. (Sani et al., 2024)

Since the initial fractions obtained from atmospheric distillation are mostly the result of physical separation, they can't break the products into smaller molecules. Those distilled heavy molecules are hardly suitable for the commercial market. Thus, refineries rely heavily on cracking processes to convert these high-molecular-weight hydrocarbons into higher-value, lighter liquid fuels. This process involves the thermal or catalytic breaking of carbon-carbon covalent bonds in long-chain alkanes. Modern chemical engineering uses Fluid Catalytic Cracking (FCC) as the primary process. The market prefers this method due to its ability to maximize high-value gasoline yields from heavy gas oils. The efficiency of FCC is highly influenced by the use of highly active, acidic zeolite catalysts. Zeolite selectively accelerates secondary hydrocarbon cracking while minimizing unwanted coke formation. Alternatively, for middle distillates such as jet fuel and diesel, hydrocracking is used. This process takes place in a high-temperature, high-pressure, hydrogen-rich environment. Over catalysts, the hydrogen saturates aromatic rings and breaks the carbon chains. (Sani et al., 2024)

=== Environmental issues ===
[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Conclusion / Your Evaluation of the Connections==

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-17T01:23:20Z

KemingWu: /* Chemical Engineering and Petroleum Products */

Add Summary Here

==Statement of connection and why you chose it==

==Main text==

=== Oil and Gas Exploration: Seismic Technology ===
Now we know the importance of oil and gas to our society, and how they were formed, the next question is where to locate them. Since reservoirs are below the surface, geologists cannot directly see where they are before drilling. This makes drilling a gamble, and that's where seismic reflection technology contributes to lowering the risk. It works as a tool that helps geologists to create an image of what is beneath the surface before they decide where to drill <ref name=":0">{{Cite journal|last=Mohammed|first=Farfour|date=2016-05-01|title=A review on multicomponent seismology: A potential seismic application for reservoir characterization|url=https://www.sciencedirect.com/science/article/pii/S2090123215001125|journal=Journal of Advanced Research|volume=3|pages=515-524}}</ref>.[[File:Seismic_Survey_and_Mechanism.png|thumb|left|500x500px|Figure 1. Seismic Technology and Mechanism for oil Exploration]]The working principle behind seismic is to use energy waves to explore underground rock layers. During a survey, energy waves are sent into the ground. When waves hit the boundaries between rock layers, some of the energy bounces back to the surface, while some goes further. Receivers then pick up these reflected waves and give information about the depth, shape and arrangement of subsurface layers by analyzing the different waves using the pre-known typical rock’s density and acoustic impedance. After processing, the data can be shown as profiles or 3D seismic images <ref>{{Cite journal|last=Ilya|first=Tsvankin|date=2010-09-01|title=Seismic anisotropy in exploration and reservoir characterization: An overview|url=https://www.researchgate.net/publication/228633261_Seismic_anisotropy_in_exploration_and_reservoir_characterization_An_overview|journal=Geophysics|volume=75}}</ref>.

This is essential because oil and gas need geological structures to build up, and seismic interpretation helps identify these structures. For example, folds show up as layers in seismic images. If the fold creates an anticline, oil and gas might move upward and get trapped near the top. Faults can be spotted when rock layers are broken or displaced. Faults can create traps but might let hydrocarbons escape as well if they aren't sealed properly. So seismic data are not just used to "find oil", they help us understand if subsurface geology has the right structure to store oil and gas<ref>{{Cite journal|last=Lawson|first=M.|date=2018-02-19|title=Geochemical applications in petroleum systems analysis: New constraints and the power of integration|url=https://www.researchgate.net/publication/323282762_Geochemical_applications_in_petroleum_systems_analysis_New_constraints_and_the_power_of_integration|journal=Geological Society, London, Special Publications|volume=468|pages=6}}</ref> . More than locating the reservoir, seismic technology also helps geologists understand its geometry. This includes the shape, thickness, depth and continuity of a reservoir. This matters because a reservoir can be located but not profitable for business. With current technology and the purpose of maximizing the future extraction, geologists are targeting large and continuous reservoirs rather than thin and isolated ones. Seismic data can help pinpoint the drilling target by showing where the reservoir might be thicker or larger<ref name=":0" /> .

An exploration workflow usually starts with a regional study. The first step is for geologists to determine if the region has a petroleum system with possible traps that contain oil. Then there are follow-up seismic surveys to get evidence and more information. Next, geoscientists interpret the data to distinguish geological structures and possible drilling targets. These decisions are assisted by other data, such as core samples. Finally, drilling locations are chosen based on different criteria <ref name=":1">{{Cite journal|last=Ma|first=Yuan Zhe|date=2011-01-01|title=Uncertainty Analysis in Reservoir Characterization and Management: How Much Should We Know About What We Don't Know?|url=https://pubs.geoscienceworld.org/aapg/books/edited-volume/1248/chapter-abstract/107059711/Uncertainty-Analysis-in-Reservoir-Characterization?redirectedFrom=fulltext|journal=AAPG Memoir|volume=1|pages=15}}</ref>.

However, seismic technology is not perfect. As an imaging technique that relies on the reflection of waves, some thin reservoirs or structures can be hard to detect. Also, seismic data cannot directly show the oil and gas but uses structures to infer their existence. Based on this limitation, seismic technology is more like a tool that reduces drilling risk than eliminates all uncertainties <ref>Saad, M. R., & Jadeer, A.-S. (2022). ''Seismic Method for Exploration Oil and Gas Reservoirs''. <nowiki>https://doi.org/10.1007/978-981-99-1964-2_89</nowiki></ref>.

=== Oil and Gas Extraction: How Geology Determines Engineering Decisions ===
Once an oil reservoir is proven as continuous and profitable, geology still plays a role in deciding how to extract the resources. In a word, engineering decisions and extraction methods are based on how the subsurface looks and how fluids move through the rock.

One of the important links between geology and engineering is reservoir quality, which mainly depends on porosity and permeability. Porosity is a measurement of how much open space exists inside the rock. This will decide how much oil, gas and water the rock can hold. Permeability refers to the connectivity of those pore spaces, deciding how easily fluids can flow between the rocks. A reservoir with high porosity can still be unproducible if those pores are not connected, so oil and gas cannot have a valid pathway to flow toward the production well. So, a high-quality reservoir needs rocks to have the ability to both store hydrocarbons and produce them <ref name=":1" />.

Engineers still need more geology information before deciding where to drill. They want to know the depth of the potential drilling trajectory, the thickness of the oil reservoir, and the fluid contacts of the reservoir to optimize the performance. For example, a rich oil-bearing zone in the reservoir should be the highest priority to place the well nearby. However, if the zone is disrupted by some faults, then engineers and geologists must determine whether these faults connect to parts of the reservoir or cut it into separate parts. Moreover, if the production well is too close to a water or gas zone, a water or gas breakthrough is likely to happen and reduce oil production. In a real-world case, a breakthrough can easily turn a high-production well into a shut-down.
[[File:Reservori_Simulation_Model.jpg|thumb|Figure 2. The reservoir modeling workflow showing the sequence of stages in data acquisition and interpretation<ref name=":2">Abel, M., Garcia, L., Lorenzatti, A., & De Ros, L. (2010, October 26). ''SEMANTIC INTEROPERABILITY IN THE PETROLEUM CHAIN: THE CONTRIBUTION OF ONTOLOGICAL ANALYSIS''.</ref>|549x549px]]

Reservoir simulation is a great tool to use in oil extraction, just like how seismic technology assists oil exploration. A reservoir model is a digital version of a reservoir with a vivid representation of reservoir structures and various relevant properties like pressure, permeability, porosity, and saturation of each phase. Engineers use this model to predict how the reservoir might behave during production. For instance, the model can estimate production rates, pressure changes, and any potential water cut. It can also achieve optimization on certain jobs, like comparing different production plans and well placement strategies. Since the model is built purely based on geological data, its quality varies depending on how well the regional geology is captured and understood, and this can also be a limitation of the reservoir model <ref name=":2" /><ref>Sambo, C., Iferobia, C. C., Babasafari, A. A., Rezaei, S., & Akanni, O. A. (2020). The Role of Time Lapse(4D) Seismic Technology as Reservoir Monitoring and Surveillance Tool: A Comprehensive Review. ''Journal of Natural Gas Science and Engineering'', ''80'', 103312. <nowiki>https://doi.org/10.1016/j.jngse.2020.103312</nowiki></ref>.

Since there are many different types of reservoirs, extraction methods have also been developed differently to achieve efficient production for each case. And they can be separated under two main reservoir types: conventional and unconventional.
{| class="wikitable"
|+
!Reservoir Type
!Geological Characteristics
!Main Extraction Methods
!Engineering
Reason
|-
|Conventional reservoirs
|High permeability and porosity for fluids to flow naturally toward the well through connected pore spaces
|Primary production relies on natural reservoir pressure and secondary recovery methods like water injection are used to maintain the pressure
|Maintain and increase reservoir pressure to improve flow toward production wells
|-
|Unconventional reservoirs
|Low permeability so fluids are trapped in rocks or exist as highly viscous bitumen
|Horizontal drilling and hydraulic fracturing are commonly used for shale gas and tight oil
For deep oil sands, steam-assisted gravity drainage can be used by injecting steam underground to heat bitumen and lower the viscousity
|Create flow pathways to make hydrocarbons mobile enough to be produced
|}
Overall, geology has a strong influence on engineering decisions in oil and gas extraction. Geology informs engineers to know the reservoir quality, what extraction methodology can be applied, and what risks might exist during production. Geological information has also been integrated into reservoir models to provide a more in-depth understanding and optimization. Oil extraction is not just about improving equipment and technology, it is also a process in which geological knowledge is applied with engineering decisions.

=== Chemical Engineering and Petroleum Products ===
[[File:Fractional Distillation.jpg|thumb|Fractional Distillation Process of Crude Oil (Wigmore Trading, n.d.)|512x512px]]
Crude oil, in its unrefined state, has almost no direct utility due to its highly complex molecular constitution. It exists fundamentally as a dense, complex mixture of hundreds of different hydrocarbons. The three basic components of crude oil are alkanes, cycloalkanes, and aromatics. The primary steps of chemical engineering within petroleum refineries are physical separation and chemical conversion. The first step separates the heterogeneous mixture into narrower, manageable fractions based on physical properties, and the second step upgrades these fractions into high-value, commercially viable products. This transformation from raw, unusable crude oil into high-value fuels relies on a sequence of thermal processes and complex catalytic reactions that manipulate molecular structures. (Sani et al., 2024)

The foundational stage of any refinery configuration is fractional distillation. It depends on the differential volatility and boiling points of the constituent hydrocarbons within crude oil. The process is commonly operationalized through the Atmospheric Distillation Unit: crude oil is preheated to approximately 350-400°C and pumped into the lowest and hottest level in the Fractional distillation tower. As the vaporized oil ascends through a series of distillation trays with temperature decreasing, it cools progressively. Hydrocarbons with lower boiling points condense at higher levels of the tower. This allows the continuous withdrawal of light fractions such as liquefied petroleum gas, naphtha, kerosene, and gas oil. (Sani et al., 2024)

Since the initial fractions obtained from atmospheric distillation are mostly the result of physical separation, they can't break the products into smaller molecules. Those distilled heavy molecules are hardly suitable for the commercial market. Thus, refineries rely heavily on cracking processes to convert these high-molecular-weight hydrocarbons into higher-value, lighter liquid fuels. This process involves the thermal or catalytic cleavage of carbon-carbon covalent bonds in long-chain alkanes. Modern chemical engineering prioritizes Fluid Catalytic Cracking (FCC) as the primary process. The market prefers this method due to its ability to maximize high-octane gasoline yields from heavy gas oils. As reviewed by Sani et al. (2024), the efficiency of FCC is highly influenced by the use of highly active, acidic zeolite catalysts. Zeolite selectively accelerates secondary hydrocarbon cracking while minimizing unwanted coke formation. Alternatively, for middle distillates such as jet fuel and diesel, hydrocracking is used. This process takes place in a high-temperature, high-pressure, hydrogen-rich environment. Over catalysts, the hydrogen saturates aromatic rings and breaks the carbon chains.

=== Environmental issues ===
[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Conclusion / Your Evaluation of the Connections==

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-17T00:22:13Z

KemingWu: /* Chemical Engineering and Petroleum Products */

Add Summary Here

==Statement of connection and why you chose it==

==Main text==

=== Oil and Gas Exploration: Seismic Technology ===
Now we know the importance of oil and gas to our society, and how they were formed, the next question is where to locate them. Since reservoirs are below the surface, geologists cannot directly see where they are before drilling. This makes drilling a gamble, and that's where seismic reflection technology contributes to lowering the risk. It works as a tool that helps geologists to create an image of what is beneath the surface before they decide where to drill <ref name=":0">{{Cite journal|last=Mohammed|first=Farfour|date=2016-05-01|title=A review on multicomponent seismology: A potential seismic application for reservoir characterization|url=https://www.sciencedirect.com/science/article/pii/S2090123215001125|journal=Journal of Advanced Research|volume=3|pages=515-524}}</ref>.[[File:Seismic_Survey_and_Mechanism.png|thumb|left|500x500px|Figure 1. Seismic Technology and Mechanism for oil Exploration]]The working principle behind seismic is to use energy waves to explore underground rock layers. During a survey, energy waves are sent into the ground. When waves hit the boundaries between rock layers, some of the energy bounces back to the surface, while some goes further. Receivers then pick up these reflected waves and give information about the depth, shape and arrangement of subsurface layers by analyzing the different waves using the pre-known typical rock’s density and acoustic impedance. After processing, the data can be shown as profiles or 3D seismic images <ref>{{Cite journal|last=Ilya|first=Tsvankin|date=2010-09-01|title=Seismic anisotropy in exploration and reservoir characterization: An overview|url=https://www.researchgate.net/publication/228633261_Seismic_anisotropy_in_exploration_and_reservoir_characterization_An_overview|journal=Geophysics|volume=75}}</ref>.

This is essential because oil and gas need geological structures to build up, and seismic interpretation helps identify these structures. For example, folds show up as layers in seismic images. If the fold creates an anticline, oil and gas might move upward and get trapped near the top. Faults can be spotted when rock layers are broken or displaced. Faults can create traps but might let hydrocarbons escape as well if they aren't sealed properly. So seismic data are not just used to "find oil", they help us understand if subsurface geology has the right structure to store oil and gas<ref>{{Cite journal|last=Lawson|first=M.|date=2018-02-19|title=Geochemical applications in petroleum systems analysis: New constraints and the power of integration|url=https://www.researchgate.net/publication/323282762_Geochemical_applications_in_petroleum_systems_analysis_New_constraints_and_the_power_of_integration|journal=Geological Society, London, Special Publications|volume=468|pages=6}}</ref> . More than locating the reservoir, seismic technology also helps geologists understand its geometry. This includes the shape, thickness, depth and continuity of a reservoir. This matters because a reservoir can be located but not profitable for business. With current technology and the purpose of maximizing the future extraction, geologists are targeting large and continuous reservoirs rather than thin and isolated ones. Seismic data can help pinpoint the drilling target by showing where the reservoir might be thicker or larger<ref name=":0" /> .

An exploration workflow usually starts with a regional study. The first step is for geologists to determine if the region has a petroleum system with possible traps that contain oil. Then there are follow-up seismic surveys to get evidence and more information. Next, geoscientists interpret the data to distinguish geological structures and possible drilling targets. These decisions are assisted by other data, such as core samples. Finally, drilling locations are chosen based on different criteria <ref name=":1">{{Cite journal|last=Ma|first=Yuan Zhe|date=2011-01-01|title=Uncertainty Analysis in Reservoir Characterization and Management: How Much Should We Know About What We Don't Know?|url=https://pubs.geoscienceworld.org/aapg/books/edited-volume/1248/chapter-abstract/107059711/Uncertainty-Analysis-in-Reservoir-Characterization?redirectedFrom=fulltext|journal=AAPG Memoir|volume=1|pages=15}}</ref>.

However, seismic technology is not perfect. As an imaging technique that relies on the reflection of waves, some thin reservoirs or structures can be hard to detect. Also, seismic data cannot directly show the oil and gas but uses structures to infer their existence. Based on this limitation, seismic technology is more like a tool that reduces drilling risk than eliminates all uncertainties <ref>Saad, M. R., & Jadeer, A.-S. (2022). ''Seismic Method for Exploration Oil and Gas Reservoirs''. <nowiki>https://doi.org/10.1007/978-981-99-1964-2_89</nowiki></ref>.

=== Oil and Gas Extraction: How Geology Determines Engineering Decisions ===
Once an oil reservoir is proven as continuous and profitable, geology still plays a role in deciding how to extract the resources. In a word, engineering decisions and extraction methods are based on how the subsurface looks and how fluids move through the rock.

One of the important links between geology and engineering is reservoir quality, which mainly depends on porosity and permeability. Porosity is a measurement of how much open space exists inside the rock. This will decide how much oil, gas and water the rock can hold. Permeability refers to the connectivity of those pore spaces, deciding how easily fluids can flow between the rocks. A reservoir with high porosity can still be unproducible if those pores are not connected, so oil and gas cannot have a valid pathway to flow toward the production well. So, a high-quality reservoir needs rocks to have the ability to both store hydrocarbons and produce them <ref name=":1" />.

Engineers still need more geology information before deciding where to drill. They want to know the depth of the potential drilling trajectory, the thickness of the oil reservoir, and the fluid contacts of the reservoir to optimize the performance. For example, a rich oil-bearing zone in the reservoir should be the highest priority to place the well nearby. However, if the zone is disrupted by some faults, then engineers and geologists must determine whether these faults connect to parts of the reservoir or cut it into separate parts. Moreover, if the production well is too close to a water or gas zone, a water or gas breakthrough is likely to happen and reduce oil production. In a real-world case, a breakthrough can easily turn a high-production well into a shut-down.
[[File:Reservori_Simulation_Model.jpg|thumb|Figure 2. The reservoir modeling workflow showing the sequence of stages in data acquisition and interpretation<ref name=":2">Abel, M., Garcia, L., Lorenzatti, A., & De Ros, L. (2010, October 26). ''SEMANTIC INTEROPERABILITY IN THE PETROLEUM CHAIN: THE CONTRIBUTION OF ONTOLOGICAL ANALYSIS''.</ref>|549x549px]]

Reservoir simulation is a great tool to use in oil extraction, just like how seismic technology assists oil exploration. A reservoir model is a digital version of a reservoir with a vivid representation of reservoir structures and various relevant properties like pressure, permeability, porosity, and saturation of each phase. Engineers use this model to predict how the reservoir might behave during production. For instance, the model can estimate production rates, pressure changes, and any potential water cut. It can also achieve optimization on certain jobs, like comparing different production plans and well placement strategies. Since the model is built purely based on geological data, its quality varies depending on how well the regional geology is captured and understood, and this can also be a limitation of the reservoir model <ref name=":2" /><ref>Sambo, C., Iferobia, C. C., Babasafari, A. A., Rezaei, S., & Akanni, O. A. (2020). The Role of Time Lapse(4D) Seismic Technology as Reservoir Monitoring and Surveillance Tool: A Comprehensive Review. ''Journal of Natural Gas Science and Engineering'', ''80'', 103312. <nowiki>https://doi.org/10.1016/j.jngse.2020.103312</nowiki></ref>.

Since there are many different types of reservoirs, extraction methods have also been developed differently to achieve efficient production for each case. And they can be separated under two main reservoir types: conventional and unconventional.
{| class="wikitable"
|+
!Reservoir Type
!Geological Characteristics
!Main Extraction Methods
!Engineering
Reason
|-
|Conventional reservoirs
|High permeability and porosity for fluids to flow naturally toward the well through connected pore spaces
|Primary production relies on natural reservoir pressure and secondary recovery methods like water injection are used to maintain the pressure
|Maintain and increase reservoir pressure to improve flow toward production wells
|-
|Unconventional reservoirs
|Low permeability so fluids are trapped in rocks or exist as highly viscous bitumen
|Horizontal drilling and hydraulic fracturing are commonly used for shale gas and tight oil
For deep oil sands, steam-assisted gravity drainage can be used by injecting steam underground to heat bitumen and lower the viscousity
|Create flow pathways to make hydrocarbons mobile enough to be produced
|}
Overall, geology has a strong influence on engineering decisions in oil and gas extraction. Geology informs engineers to know the reservoir quality, what extraction methodology can be applied, and what risks might exist during production. Geological information has also been integrated into reservoir models to provide a more in-depth understanding and optimization. Oil extraction is not just about improving equipment and technology, it is also a process in which geological knowledge is applied with engineering decisions.

=== Chemical Engineering and Petroleum Products ===
[[File:Fractional Distillation.jpg|thumb|Fractional Distillation Process of Crude Oil (Wigmore Trading, n.d.)|512x512px]]
Crude oil, in its unrefined state, has almost no direct utility due to its highly complex molecular constitution. It exists fundamentally as a dense, complex mixture of hundreds of different hydrocarbons. The three basic components of crude oil are alkanes, cycloalkanes, and aromatics. The primary steps of chemical engineering within petroleum refineries are physical separation and chemical conversion. The first step separates the heterogeneous mixture into narrower, manageable fractions based on physical properties, and the second step upgrades these fractions into high-value, commercially viable products. This transformation from raw, unusable crude oil into high-value fuels relies on a sequence of thermal processes and complex catalytic reactions that manipulate molecular structures. (Sani et al., 2024)

The foundational stage of any refinery configuration is fractional distillation. It depends on the differential volatility and boiling points of the constituent hydrocarbons within crude oil. The process is commonly operationalized through the Atmospheric Distillation Unit: crude oil is preheated to approximately 350-400°C and pumped into the lowest and hottest level in the Fractional distillation tower. As the vaporized oil ascends through a series of distillation trays with temperature decreasing, it cools progressively. Hydrocarbons with lower boiling points condense at higher levels of the tower. This allows the continuous withdrawal of light fractions such as liquefied petroleum gas, naphtha, kerosene, and gas oil. (Sani et al., 2024)

=== Environmental issues ===
[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Conclusion / Your Evaluation of the Connections==

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-17T00:21:25Z

KemingWu: /* Chemical Engineering and Petroleum Products */

Add Summary Here

==Statement of connection and why you chose it==

==Main text==

=== Oil and Gas Exploration: Seismic Technology ===
Now we know the importance of oil and gas to our society, and how they were formed, the next question is where to locate them. Since reservoirs are below the surface, geologists cannot directly see where they are before drilling. This makes drilling a gamble, and that's where seismic reflection technology contributes to lowering the risk. It works as a tool that helps geologists to create an image of what is beneath the surface before they decide where to drill <ref name=":0">{{Cite journal|last=Mohammed|first=Farfour|date=2016-05-01|title=A review on multicomponent seismology: A potential seismic application for reservoir characterization|url=https://www.sciencedirect.com/science/article/pii/S2090123215001125|journal=Journal of Advanced Research|volume=3|pages=515-524}}</ref>.[[File:Seismic_Survey_and_Mechanism.png|thumb|left|500x500px|Figure 1. Seismic Technology and Mechanism for oil Exploration]]The working principle behind seismic is to use energy waves to explore underground rock layers. During a survey, energy waves are sent into the ground. When waves hit the boundaries between rock layers, some of the energy bounces back to the surface, while some goes further. Receivers then pick up these reflected waves and give information about the depth, shape and arrangement of subsurface layers by analyzing the different waves using the pre-known typical rock’s density and acoustic impedance. After processing, the data can be shown as profiles or 3D seismic images <ref>{{Cite journal|last=Ilya|first=Tsvankin|date=2010-09-01|title=Seismic anisotropy in exploration and reservoir characterization: An overview|url=https://www.researchgate.net/publication/228633261_Seismic_anisotropy_in_exploration_and_reservoir_characterization_An_overview|journal=Geophysics|volume=75}}</ref>.

This is essential because oil and gas need geological structures to build up, and seismic interpretation helps identify these structures. For example, folds show up as layers in seismic images. If the fold creates an anticline, oil and gas might move upward and get trapped near the top. Faults can be spotted when rock layers are broken or displaced. Faults can create traps but might let hydrocarbons escape as well if they aren't sealed properly. So seismic data are not just used to "find oil", they help us understand if subsurface geology has the right structure to store oil and gas<ref>{{Cite journal|last=Lawson|first=M.|date=2018-02-19|title=Geochemical applications in petroleum systems analysis: New constraints and the power of integration|url=https://www.researchgate.net/publication/323282762_Geochemical_applications_in_petroleum_systems_analysis_New_constraints_and_the_power_of_integration|journal=Geological Society, London, Special Publications|volume=468|pages=6}}</ref> . More than locating the reservoir, seismic technology also helps geologists understand its geometry. This includes the shape, thickness, depth and continuity of a reservoir. This matters because a reservoir can be located but not profitable for business. With current technology and the purpose of maximizing the future extraction, geologists are targeting large and continuous reservoirs rather than thin and isolated ones. Seismic data can help pinpoint the drilling target by showing where the reservoir might be thicker or larger<ref name=":0" /> .

An exploration workflow usually starts with a regional study. The first step is for geologists to determine if the region has a petroleum system with possible traps that contain oil. Then there are follow-up seismic surveys to get evidence and more information. Next, geoscientists interpret the data to distinguish geological structures and possible drilling targets. These decisions are assisted by other data, such as core samples. Finally, drilling locations are chosen based on different criteria <ref name=":1">{{Cite journal|last=Ma|first=Yuan Zhe|date=2011-01-01|title=Uncertainty Analysis in Reservoir Characterization and Management: How Much Should We Know About What We Don't Know?|url=https://pubs.geoscienceworld.org/aapg/books/edited-volume/1248/chapter-abstract/107059711/Uncertainty-Analysis-in-Reservoir-Characterization?redirectedFrom=fulltext|journal=AAPG Memoir|volume=1|pages=15}}</ref>.

However, seismic technology is not perfect. As an imaging technique that relies on the reflection of waves, some thin reservoirs or structures can be hard to detect. Also, seismic data cannot directly show the oil and gas but uses structures to infer their existence. Based on this limitation, seismic technology is more like a tool that reduces drilling risk than eliminates all uncertainties <ref>Saad, M. R., & Jadeer, A.-S. (2022). ''Seismic Method for Exploration Oil and Gas Reservoirs''. <nowiki>https://doi.org/10.1007/978-981-99-1964-2_89</nowiki></ref>.

=== Oil and Gas Extraction: How Geology Determines Engineering Decisions ===
Once an oil reservoir is proven as continuous and profitable, geology still plays a role in deciding how to extract the resources. In a word, engineering decisions and extraction methods are based on how the subsurface looks and how fluids move through the rock.

One of the important links between geology and engineering is reservoir quality, which mainly depends on porosity and permeability. Porosity is a measurement of how much open space exists inside the rock. This will decide how much oil, gas and water the rock can hold. Permeability refers to the connectivity of those pore spaces, deciding how easily fluids can flow between the rocks. A reservoir with high porosity can still be unproducible if those pores are not connected, so oil and gas cannot have a valid pathway to flow toward the production well. So, a high-quality reservoir needs rocks to have the ability to both store hydrocarbons and produce them <ref name=":1" />.

Engineers still need more geology information before deciding where to drill. They want to know the depth of the potential drilling trajectory, the thickness of the oil reservoir, and the fluid contacts of the reservoir to optimize the performance. For example, a rich oil-bearing zone in the reservoir should be the highest priority to place the well nearby. However, if the zone is disrupted by some faults, then engineers and geologists must determine whether these faults connect to parts of the reservoir or cut it into separate parts. Moreover, if the production well is too close to a water or gas zone, a water or gas breakthrough is likely to happen and reduce oil production. In a real-world case, a breakthrough can easily turn a high-production well into a shut-down.
[[File:Reservori_Simulation_Model.jpg|thumb|Figure 2. The reservoir modeling workflow showing the sequence of stages in data acquisition and interpretation<ref name=":2">Abel, M., Garcia, L., Lorenzatti, A., & De Ros, L. (2010, October 26). ''SEMANTIC INTEROPERABILITY IN THE PETROLEUM CHAIN: THE CONTRIBUTION OF ONTOLOGICAL ANALYSIS''.</ref>|549x549px]]

Reservoir simulation is a great tool to use in oil extraction, just like how seismic technology assists oil exploration. A reservoir model is a digital version of a reservoir with a vivid representation of reservoir structures and various relevant properties like pressure, permeability, porosity, and saturation of each phase. Engineers use this model to predict how the reservoir might behave during production. For instance, the model can estimate production rates, pressure changes, and any potential water cut. It can also achieve optimization on certain jobs, like comparing different production plans and well placement strategies. Since the model is built purely based on geological data, its quality varies depending on how well the regional geology is captured and understood, and this can also be a limitation of the reservoir model <ref name=":2" /><ref>Sambo, C., Iferobia, C. C., Babasafari, A. A., Rezaei, S., & Akanni, O. A. (2020). The Role of Time Lapse(4D) Seismic Technology as Reservoir Monitoring and Surveillance Tool: A Comprehensive Review. ''Journal of Natural Gas Science and Engineering'', ''80'', 103312. <nowiki>https://doi.org/10.1016/j.jngse.2020.103312</nowiki></ref>.

Since there are many different types of reservoirs, extraction methods have also been developed differently to achieve efficient production for each case. And they can be separated under two main reservoir types: conventional and unconventional.
{| class="wikitable"
|+
!Reservoir Type
!Geological Characteristics
!Main Extraction Methods
!Engineering
Reason
|-
|Conventional reservoirs
|High permeability and porosity for fluids to flow naturally toward the well through connected pore spaces
|Primary production relies on natural reservoir pressure and secondary recovery methods like water injection are used to maintain the pressure
|Maintain and increase reservoir pressure to improve flow toward production wells
|-
|Unconventional reservoirs
|Low permeability so fluids are trapped in rocks or exist as highly viscous bitumen
|Horizontal drilling and hydraulic fracturing are commonly used for shale gas and tight oil
For deep oil sands, steam-assisted gravity drainage can be used by injecting steam underground to heat bitumen and lower the viscousity
|Create flow pathways to make hydrocarbons mobile enough to be produced
|}
Overall, geology has a strong influence on engineering decisions in oil and gas extraction. Geology informs engineers to know the reservoir quality, what extraction methodology can be applied, and what risks might exist during production. Geological information has also been integrated into reservoir models to provide a more in-depth understanding and optimization. Oil extraction is not just about improving equipment and technology, it is also a process in which geological knowledge is applied with engineering decisions.

=== Chemical Engineering and Petroleum Products ===
[[File:Fractional Distillation.jpg|thumb|Fractional Distillation Process of Crude Oil (Wigmore Trading, n.d.)]]
Crude oil, in its unrefined state, has almost no direct utility due to its highly complex molecular constitution. It exists fundamentally as a dense, complex mixture of hundreds of different hydrocarbons. The three basic components of crude oil are alkanes, cycloalkanes, and aromatics. The primary steps of chemical engineering within petroleum refineries are physical separation and chemical conversion. The first step separates the heterogeneous mixture into narrower, manageable fractions based on physical properties, and the second step upgrades these fractions into high-value, commercially viable products. This transformation from raw, unusable crude oil into high-value fuels relies on a sequence of thermal processes and complex catalytic reactions that manipulate molecular structures. (Sani et al., 2024)

The foundational stage of any refinery configuration is fractional distillation. It depends on the differential volatility and boiling points of the constituent hydrocarbons within crude oil. The process is commonly operationalized through the Atmospheric Distillation Unit: crude oil is preheated to approximately 350-400°C and pumped into the lowest and hottest level in the Fractional distillation tower. As the vaporized oil ascends through a series of distillation trays with temperature decreasing, it cools progressively. Hydrocarbons with lower boiling points condense at higher levels of the tower. This allows the continuous withdrawal of light fractions such as liquefied petroleum gas, naphtha, kerosene, and gas oil. (Sani et al., 2024)

=== Environmental issues ===
[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Conclusion / Your Evaluation of the Connections==

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-17T00:14:50Z

KemingWu: /* Chemical Engineering and Petroleum Products */

Add Summary Here

==Statement of connection and why you chose it==

==Main text==

=== Oil and Gas Exploration: Seismic Technology ===
Now we know the importance of oil and gas to our society, and how they were formed, the next question is where to locate them. Since reservoirs are below the surface, geologists cannot directly see where they are before drilling. This makes drilling a gamble, and that's where seismic reflection technology contributes to lowering the risk. It works as a tool that helps geologists to create an image of what is beneath the surface before they decide where to drill <ref name=":0">{{Cite journal|last=Mohammed|first=Farfour|date=2016-05-01|title=A review on multicomponent seismology: A potential seismic application for reservoir characterization|url=https://www.sciencedirect.com/science/article/pii/S2090123215001125|journal=Journal of Advanced Research|volume=3|pages=515-524}}</ref>.[[File:Seismic_Survey_and_Mechanism.png|thumb|left|500x500px|Figure 1. Seismic Technology and Mechanism for oil Exploration]]The working principle behind seismic is to use energy waves to explore underground rock layers. During a survey, energy waves are sent into the ground. When waves hit the boundaries between rock layers, some of the energy bounces back to the surface, while some goes further. Receivers then pick up these reflected waves and give information about the depth, shape and arrangement of subsurface layers by analyzing the different waves using the pre-known typical rock’s density and acoustic impedance. After processing, the data can be shown as profiles or 3D seismic images <ref>{{Cite journal|last=Ilya|first=Tsvankin|date=2010-09-01|title=Seismic anisotropy in exploration and reservoir characterization: An overview|url=https://www.researchgate.net/publication/228633261_Seismic_anisotropy_in_exploration_and_reservoir_characterization_An_overview|journal=Geophysics|volume=75}}</ref>.

This is essential because oil and gas need geological structures to build up, and seismic interpretation helps identify these structures. For example, folds show up as layers in seismic images. If the fold creates an anticline, oil and gas might move upward and get trapped near the top. Faults can be spotted when rock layers are broken or displaced. Faults can create traps but might let hydrocarbons escape as well if they aren't sealed properly. So seismic data are not just used to "find oil", they help us understand if subsurface geology has the right structure to store oil and gas<ref>{{Cite journal|last=Lawson|first=M.|date=2018-02-19|title=Geochemical applications in petroleum systems analysis: New constraints and the power of integration|url=https://www.researchgate.net/publication/323282762_Geochemical_applications_in_petroleum_systems_analysis_New_constraints_and_the_power_of_integration|journal=Geological Society, London, Special Publications|volume=468|pages=6}}</ref> . More than locating the reservoir, seismic technology also helps geologists understand its geometry. This includes the shape, thickness, depth and continuity of a reservoir. This matters because a reservoir can be located but not profitable for business. With current technology and the purpose of maximizing the future extraction, geologists are targeting large and continuous reservoirs rather than thin and isolated ones. Seismic data can help pinpoint the drilling target by showing where the reservoir might be thicker or larger<ref name=":0" /> .

An exploration workflow usually starts with a regional study. The first step is for geologists to determine if the region has a petroleum system with possible traps that contain oil. Then there are follow-up seismic surveys to get evidence and more information. Next, geoscientists interpret the data to distinguish geological structures and possible drilling targets. These decisions are assisted by other data, such as core samples. Finally, drilling locations are chosen based on different criteria <ref name=":1">{{Cite journal|last=Ma|first=Yuan Zhe|date=2011-01-01|title=Uncertainty Analysis in Reservoir Characterization and Management: How Much Should We Know About What We Don't Know?|url=https://pubs.geoscienceworld.org/aapg/books/edited-volume/1248/chapter-abstract/107059711/Uncertainty-Analysis-in-Reservoir-Characterization?redirectedFrom=fulltext|journal=AAPG Memoir|volume=1|pages=15}}</ref>.

However, seismic technology is not perfect. As an imaging technique that relies on the reflection of waves, some thin reservoirs or structures can be hard to detect. Also, seismic data cannot directly show the oil and gas but uses structures to infer their existence. Based on this limitation, seismic technology is more like a tool that reduces drilling risk than eliminates all uncertainties <ref>Saad, M. R., & Jadeer, A.-S. (2022). ''Seismic Method for Exploration Oil and Gas Reservoirs''. <nowiki>https://doi.org/10.1007/978-981-99-1964-2_89</nowiki></ref>.

=== Oil and Gas Extraction: How Geology Determines Engineering Decisions ===
Once an oil reservoir is proven as continuous and profitable, geology still plays a role in deciding how to extract the resources. In a word, engineering decisions and extraction methods are based on how the subsurface looks and how fluids move through the rock.

One of the important links between geology and engineering is reservoir quality, which mainly depends on porosity and permeability. Porosity is a measurement of how much open space exists inside the rock. This will decide how much oil, gas and water the rock can hold. Permeability refers to the connectivity of those pore spaces, deciding how easily fluids can flow between the rocks. A reservoir with high porosity can still be unproducible if those pores are not connected, so oil and gas cannot have a valid pathway to flow toward the production well. So, a high-quality reservoir needs rocks to have the ability to both store hydrocarbons and produce them <ref name=":1" />.

Engineers still need more geology information before deciding where to drill. They want to know the depth of the potential drilling trajectory, the thickness of the oil reservoir, and the fluid contacts of the reservoir to optimize the performance. For example, a rich oil-bearing zone in the reservoir should be the highest priority to place the well nearby. However, if the zone is disrupted by some faults, then engineers and geologists must determine whether these faults connect to parts of the reservoir or cut it into separate parts. Moreover, if the production well is too close to a water or gas zone, a water or gas breakthrough is likely to happen and reduce oil production. In a real-world case, a breakthrough can easily turn a high-production well into a shut-down.
[[File:Reservori_Simulation_Model.jpg|thumb|Figure 2. The reservoir modeling workflow showing the sequence of stages in data acquisition and interpretation<ref name=":2">Abel, M., Garcia, L., Lorenzatti, A., & De Ros, L. (2010, October 26). ''SEMANTIC INTEROPERABILITY IN THE PETROLEUM CHAIN: THE CONTRIBUTION OF ONTOLOGICAL ANALYSIS''.</ref>|549x549px]]

Reservoir simulation is a great tool to use in oil extraction, just like how seismic technology assists oil exploration. A reservoir model is a digital version of a reservoir with a vivid representation of reservoir structures and various relevant properties like pressure, permeability, porosity, and saturation of each phase. Engineers use this model to predict how the reservoir might behave during production. For instance, the model can estimate production rates, pressure changes, and any potential water cut. It can also achieve optimization on certain jobs, like comparing different production plans and well placement strategies. Since the model is built purely based on geological data, its quality varies depending on how well the regional geology is captured and understood, and this can also be a limitation of the reservoir model <ref name=":2" /><ref>Sambo, C., Iferobia, C. C., Babasafari, A. A., Rezaei, S., & Akanni, O. A. (2020). The Role of Time Lapse(4D) Seismic Technology as Reservoir Monitoring and Surveillance Tool: A Comprehensive Review. ''Journal of Natural Gas Science and Engineering'', ''80'', 103312. <nowiki>https://doi.org/10.1016/j.jngse.2020.103312</nowiki></ref>.

Since there are many different types of reservoirs, extraction methods have also been developed differently to achieve efficient production for each case. And they can be separated under two main reservoir types: conventional and unconventional.
{| class="wikitable"
|+
!Reservoir Type
!Geological Characteristics
!Main Extraction Methods
!Engineering
Reason
|-
|Conventional reservoirs
|High permeability and porosity for fluids to flow naturally toward the well through connected pore spaces
|Primary production relies on natural reservoir pressure and secondary recovery methods like water injection are used to maintain the pressure
|Maintain and increase reservoir pressure to improve flow toward production wells
|-
|Unconventional reservoirs
|Low permeability so fluids are trapped in rocks or exist as highly viscous bitumen
|Horizontal drilling and hydraulic fracturing are commonly used for shale gas and tight oil
For deep oil sands, steam-assisted gravity drainage can be used by injecting steam underground to heat bitumen and lower the viscousity
|Create flow pathways to make hydrocarbons mobile enough to be produced
|}
Overall, geology has a strong influence on engineering decisions in oil and gas extraction. Geology informs engineers to know the reservoir quality, what extraction methodology can be applied, and what risks might exist during production. Geological information has also been integrated into reservoir models to provide a more in-depth understanding and optimization. Oil extraction is not just about improving equipment and technology, it is also a process in which geological knowledge is applied with engineering decisions.

=== Chemical Engineering and Petroleum Products ===
[[File:Fractional Distillation.jpg|thumb|Fractional Distillation Process of Crude Oil]]
Crude oil, in its unrefined state, has almost no direct utility due to its highly complex molecular constitution. It exists fundamentally as a dense, complex mixture of hundreds of different hydrocarbons. The three basic components of crude oil are alkanes, cycloalkanes, and aromatics. The primary steps of chemical engineering within petroleum refineries are physical separation and chemical conversion. The first step separates the heterogeneous mixture into narrower, manageable fractions based on physical properties, and the second step upgrades these fractions into high-value, commercially viable products. This transformation from raw, unusable crude oil into high-value fuels relies on a sequence of thermal processes and complex catalytic reactions that manipulate molecular structures. (Sani et al., 2024)

=== Environmental issues ===
[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Conclusion / Your Evaluation of the Connections==

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

File:Fractional Distillation.jpg

2026-06-17T00:13:42Z

KemingWu: Uploaded a work by {{Unknown|author}} from https://wigmoretrading.com/what-is-the-fractional-distillation-process-of-oil-in-nigeria/ with UploadWizard

=={{int:filedesc}}==
{{Information
|description={{en|1=Fractional Distillation Tower Working Mechanism graph}}
|date=2026-01
|source=https://wigmoretrading.com/what-is-the-fractional-distillation-process-of-oil-in-nigeria/
|author={{Unknown|author}}
|permission=
|other versions=
}}

=={{int:license-header}}==
{{cr-cdn-exp}}

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-16T23:34:27Z

KemingWu: /* Chemical Engineering and Petroleum Products */

Add Summary Here

==Statement of connection and why you chose it==

==Main text==

=== Oil and Gas Exploration: Seismic Technology ===
Now we know the importance of oil and gas to our society, and how they were formed, the next question is where to locate them. Since reservoirs are below the surface, geologists cannot directly see where they are before drilling. This makes drilling a gamble, and that's where seismic reflection technology contributes to lowering the risk. It works as a tool that helps geologists to create an image of what is beneath the surface before they decide where to drill <ref name=":0">{{Cite journal|last=Mohammed|first=Farfour|date=2016-05-01|title=A review on multicomponent seismology: A potential seismic application for reservoir characterization|url=https://www.sciencedirect.com/science/article/pii/S2090123215001125|journal=Journal of Advanced Research|volume=3|pages=515-524}}</ref>.[[File:Seismic_Survey_and_Mechanism.png|thumb|left|500x500px|Figure 1. Seismic Technology and Mechanism for oil Exploration]]The working principle behind seismic is to use energy waves to explore underground rock layers. During a survey, energy waves are sent into the ground. When waves hit the boundaries between rock layers, some of the energy bounces back to the surface, while some goes further. Receivers then pick up these reflected waves and give information about the depth, shape and arrangement of subsurface layers by analyzing the different waves using the pre-known typical rock’s density and acoustic impedance. After processing, the data can be shown as profiles or 3D seismic images <ref>{{Cite journal|last=Ilya|first=Tsvankin|date=2010-09-01|title=Seismic anisotropy in exploration and reservoir characterization: An overview|url=https://www.researchgate.net/publication/228633261_Seismic_anisotropy_in_exploration_and_reservoir_characterization_An_overview|journal=Geophysics|volume=75}}</ref>.

This is essential because oil and gas need geological structures to build up, and seismic interpretation helps identify these structures. For example, folds show up as layers in seismic images. If the fold creates an anticline, oil and gas might move upward and get trapped near the top. Faults can be spotted when rock layers are broken or displaced. Faults can create traps but might let hydrocarbons escape as well if they aren't sealed properly. So seismic data are not just used to "find oil", they help us understand if subsurface geology has the right structure to store oil and gas<ref>{{Cite journal|last=Lawson|first=M.|date=2018-02-19|title=Geochemical applications in petroleum systems analysis: New constraints and the power of integration|url=https://www.researchgate.net/publication/323282762_Geochemical_applications_in_petroleum_systems_analysis_New_constraints_and_the_power_of_integration|journal=Geological Society, London, Special Publications|volume=468|pages=6}}</ref> . More than locating the reservoir, seismic technology also helps geologists understand its geometry. This includes the shape, thickness, depth and continuity of a reservoir. This matters because a reservoir can be located but not profitable for business. With current technology and the purpose of maximizing the future extraction, geologists are targeting large and continuous reservoirs rather than thin and isolated ones. Seismic data can help pinpoint the drilling target by showing where the reservoir might be thicker or larger<ref name=":0" /> .

An exploration workflow usually starts with a regional study. The first step is for geologists to determine if the region has a petroleum system with possible traps that contain oil. Then there are follow-up seismic surveys to get evidence and more information. Next, geoscientists interpret the data to distinguish geological structures and possible drilling targets. These decisions are assisted by other data, such as core samples. Finally, drilling locations are chosen based on different criteria <ref name=":1">{{Cite journal|last=Ma|first=Yuan Zhe|date=2011-01-01|title=Uncertainty Analysis in Reservoir Characterization and Management: How Much Should We Know About What We Don't Know?|url=https://pubs.geoscienceworld.org/aapg/books/edited-volume/1248/chapter-abstract/107059711/Uncertainty-Analysis-in-Reservoir-Characterization?redirectedFrom=fulltext|journal=AAPG Memoir|volume=1|pages=15}}</ref>.

However, seismic technology is not perfect. As an imaging technique that relies on the reflection of waves, some thin reservoirs or structures can be hard to detect. Also, seismic data cannot directly show the oil and gas but uses structures to infer their existence. Based on this limitation, seismic technology is more like a tool that reduces drilling risk than eliminates all uncertainties <ref>Saad, M. R., & Jadeer, A.-S. (2022). ''Seismic Method for Exploration Oil and Gas Reservoirs''. <nowiki>https://doi.org/10.1007/978-981-99-1964-2_89</nowiki></ref>.

=== Oil and Gas Extraction: How Geology Determines Engineering Decisions ===
Once an oil reservoir is proven as continuous and profitable, geology still plays a role in deciding how to extract the resources. In a word, engineering decisions and extraction methods are based on how the subsurface looks and how fluids move through the rock.

One of the important links between geology and engineering is reservoir quality, which mainly depends on porosity and permeability. Porosity is a measurement of how much open space exists inside the rock. This will decide how much oil, gas and water the rock can hold. Permeability refers to the connectivity of those pore spaces, deciding how easily fluids can flow between the rocks. A reservoir with high porosity can still be unproducible if those pores are not connected, so oil and gas cannot have a valid pathway to flow toward the production well. So, a high-quality reservoir needs rocks to have the ability to both store hydrocarbons and produce them <ref name=":1" />.

Engineers still need more geology information before deciding where to drill. They want to know the depth of the potential drilling trajectory, the thickness of the oil reservoir, and the fluid contacts of the reservoir to optimize the performance. For example, a rich oil-bearing zone in the reservoir should be the highest priority to place the well nearby. However, if the zone is disrupted by some faults, then engineers and geologists must determine whether these faults connect to parts of the reservoir or cut it into separate parts. Moreover, if the production well is too close to a water or gas zone, a water or gas breakthrough is likely to happen and reduce oil production. In a real-world case, a breakthrough can easily turn a high-production well into a shut-down.
[[File:Reservori_Simulation_Model.jpg|thumb|Figure 2. The reservoir modeling workflow showing the sequence of stages in data acquisition and interpretation<ref name=":2">Abel, M., Garcia, L., Lorenzatti, A., & De Ros, L. (2010, October 26). ''SEMANTIC INTEROPERABILITY IN THE PETROLEUM CHAIN: THE CONTRIBUTION OF ONTOLOGICAL ANALYSIS''.</ref>|549x549px]]

Reservoir simulation is a great tool to use in oil extraction, just like how seismic technology assists oil exploration. A reservoir model is a digital version of a reservoir with a vivid representation of reservoir structures and various relevant properties like pressure, permeability, porosity, and saturation of each phase. Engineers use this model to predict how the reservoir might behave during production. For instance, the model can estimate production rates, pressure changes, and any potential water cut. It can also achieve optimization on certain jobs, like comparing different production plans and well placement strategies. Since the model is built purely based on geological data, its quality varies depending on how well the regional geology is captured and understood, and this can also be a limitation of the reservoir model <ref name=":2" /><ref>Sambo, C., Iferobia, C. C., Babasafari, A. A., Rezaei, S., & Akanni, O. A. (2020). The Role of Time Lapse(4D) Seismic Technology as Reservoir Monitoring and Surveillance Tool: A Comprehensive Review. ''Journal of Natural Gas Science and Engineering'', ''80'', 103312. <nowiki>https://doi.org/10.1016/j.jngse.2020.103312</nowiki></ref>.

Since there are many different types of reservoirs, extraction methods have also been developed differently to achieve efficient production for each case. And they can be separated under two main reservoir types: conventional and unconventional.
{| class="wikitable"
|+
!Reservoir Type
!Geological Characteristics
!Main Extraction Methods
!Engineering
Reason
|-
|Conventional reservoirs
|High permeability and porosity for fluids to flow naturally toward the well through connected pore spaces
|Primary production relies on natural reservoir pressure and secondary recovery methods like water injection are used to maintain the pressure
|Maintain and increase reservoir pressure to improve flow toward production wells
|-
|Unconventional reservoirs
|Low permeability so fluids are trapped in rocks or exist as highly viscous bitumen
|Horizontal drilling and hydraulic fracturing are commonly used for shale gas and tight oil
For deep oil sands, steam-assisted gravity drainage can be used by injecting steam underground to heat bitumen and lower the viscousity
|Create flow pathways to make hydrocarbons mobile enough to be produced
|}
Overall, geology has a strong influence on engineering decisions in oil and gas extraction. Geology informs engineers to know the reservoir quality, what extraction methodology can be applied, and what risks might exist during production. Geological information has also been integrated into reservoir models to provide a more in-depth understanding and optimization. Oil extraction is not just about improving equipment and technology, it is also a process in which geological knowledge is applied with engineering decisions.

=== Chemical Engineering and Petroleum Products ===
Crude oil, in its unrefined state, has almost no direct utility due to its highly complex molecular constitution. It exists fundamentally as a dense, complex mixture of hundreds of different hydrocarbons. The three basic components of crude oil are alkanes, cycloalkanes, and aromatics. The primary steps of chemical engineering within petroleum refineries are physical separation and chemical conversion. The first step separates the heterogeneous mixture into narrower, manageable fractions based on physical properties, and the second step upgrades these fractions into high-value, commercially viable products. This transformation from raw, unusable crude oil into high-value fuels relies on a sequence of thermal processes and complex catalytic reactions that manipulate molecular structures. (Sani et al., 2024)

=== Environmental issues ===
[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Conclusion / Your Evaluation of the Connections==

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-16T06:49:28Z

KemingWu: /* Main text */

Add Summary Here

==Statement of connection and why you chose it==

==Main text==

=== Oil and Gas Exploration: Seismic Technology ===
Now we know the importance of oil and gas to our society, and how they were formed, the next question is where to locate them. Since reservoirs are below the surface, geologists cannot directly see where they are before drilling. This makes drilling a gamble, and that's where seismic reflection technology contributes to lowering the risk. It works as a tool that helps geologists to create an image of what is beneath the surface before they decide where to drill <ref name=":0">{{Cite journal|last=Mohammed|first=Farfour|date=2016-05-01|title=A review on multicomponent seismology: A potential seismic application for reservoir characterization|url=https://www.sciencedirect.com/science/article/pii/S2090123215001125|journal=Journal of Advanced Research|volume=3|pages=515-524}}</ref>.[[File:Seismic_Survey_and_Mechanism.png|thumb|left|500x500px|Figure 1. Seismic Technology and Mechanism for oil Exploration]]The working principle behind seismic is to use energy waves to explore underground rock layers. During a survey, energy waves are sent into the ground. When waves hit the boundaries between rock layers, some of the energy bounces back to the surface, while some goes further. Receivers then pick up these reflected waves and give information about the depth, shape and arrangement of subsurface layers by analyzing the different waves using the pre-known typical rock’s density and acoustic impedance. After processing, the data can be shown as profiles or 3D seismic images <ref>{{Cite journal|last=Ilya|first=Tsvankin|date=2010-09-01|title=Seismic anisotropy in exploration and reservoir characterization: An overview|url=https://www.researchgate.net/publication/228633261_Seismic_anisotropy_in_exploration_and_reservoir_characterization_An_overview|journal=Geophysics|volume=75}}</ref>.

This is essential because oil and gas need geological structures to build up, and seismic interpretation helps identify these structures. For example, folds show up as layers in seismic images. If the fold creates an anticline, oil and gas might move upward and get trapped near the top. Faults can be spotted when rock layers are broken or displaced. Faults can create traps but might let hydrocarbons escape as well if they aren't sealed properly. So seismic data are not just used to "find oil", they help us understand if subsurface geology has the right structure to store oil and gas<ref>{{Cite journal|last=Lawson|first=M.|date=2018-02-19|title=Geochemical applications in petroleum systems analysis: New constraints and the power of integration|url=https://www.researchgate.net/publication/323282762_Geochemical_applications_in_petroleum_systems_analysis_New_constraints_and_the_power_of_integration|journal=Geological Society, London, Special Publications|volume=468|pages=6}}</ref> . More than locating the reservoir, seismic technology also helps geologists understand its geometry. This includes the shape, thickness, depth and continuity of a reservoir. This matters because a reservoir can be located but not profitable for business. With current technology and the purpose of maximizing the future extraction, geologists are targeting large and continuous reservoirs rather than thin and isolated ones. Seismic data can help pinpoint the drilling target by showing where the reservoir might be thicker or larger<ref name=":0" /> .

An exploration workflow usually starts with a regional study. The first step is for geologists to determine if the region has a petroleum system with possible traps that contain oil. Then there are follow-up seismic surveys to get evidence and more information. Next, geoscientists interpret the data to distinguish geological structures and possible drilling targets. These decisions are assisted by other data, such as core samples. Finally, drilling locations are chosen based on different criteria <ref name=":1">{{Cite journal|last=Ma|first=Yuan Zhe|date=2011-01-01|title=Uncertainty Analysis in Reservoir Characterization and Management: How Much Should We Know About What We Don't Know?|url=https://pubs.geoscienceworld.org/aapg/books/edited-volume/1248/chapter-abstract/107059711/Uncertainty-Analysis-in-Reservoir-Characterization?redirectedFrom=fulltext|journal=AAPG Memoir|volume=1|pages=15}}</ref>.

However, seismic technology is not perfect. As an imaging technique that relies on the reflection of waves, some thin reservoirs or structures can be hard to detect. Also, seismic data cannot directly show the oil and gas but uses structures to infer their existence. Based on this limitation, seismic technology is more like a tool that reduces drilling risk than eliminates all uncertainties <ref>Saad, M. R., & Jadeer, A.-S. (2022). ''Seismic Method for Exploration Oil and Gas Reservoirs''. <nowiki>https://doi.org/10.1007/978-981-99-1964-2_89</nowiki></ref>.

=== Oil and Gas Extraction: How Geology Determines Engineering Decisions ===
Once an oil reservoir is proven as continuous and profitable, geology still plays a role in deciding how to extract the resources. In a word, engineering decisions and extraction methods are based on how the subsurface looks and how fluids move through the rock.

One of the important links between geology and engineering is reservoir quality, which mainly depends on porosity and permeability. Porosity is a measurement of how much open space exists inside the rock. This will decide how much oil, gas and water the rock can hold. Permeability refers to the connectivity of those pore spaces, deciding how easily fluids can flow between the rocks. A reservoir with high porosity can still be unproducible if those pores are not connected, so oil and gas cannot have a valid pathway to flow toward the production well. So, a high-quality reservoir needs rocks to have the ability to both store hydrocarbons and produce them <ref name=":1" />.

Engineers still need more geology information before deciding where to drill. They want to know the depth of the potential drilling trajectory, the thickness of the oil reservoir, and the fluid contacts of the reservoir to optimize the performance. For example, a rich oil-bearing zone in the reservoir should be the highest priority to place the well nearby. However, if the zone is disrupted by some faults, then engineers and geologists must determine whether these faults connect to parts of the reservoir or cut it into separate parts. Moreover, if the production well is too close to a water or gas zone, a water or gas breakthrough is likely to happen and reduce oil production. In a real-world case, a breakthrough can easily turn a high-production well into a shut-down.
[[File:Reservori_Simulation_Model.jpg|thumb|Figure 2. The reservoir modeling workflow showing the sequence of stages in data acquisition and interpretation<ref name=":2">Abel, M., Garcia, L., Lorenzatti, A., & De Ros, L. (2010, October 26). ''SEMANTIC INTEROPERABILITY IN THE PETROLEUM CHAIN: THE CONTRIBUTION OF ONTOLOGICAL ANALYSIS''.</ref>|549x549px]]

Reservoir simulation is a great tool to use in oil extraction, just like how seismic technology assists oil exploration. A reservoir model is a digital version of a reservoir with a vivid representation of reservoir structures and various relevant properties like pressure, permeability, porosity, and saturation of each phase. Engineers use this model to predict how the reservoir might behave during production. For instance, the model can estimate production rates, pressure changes, and any potential water cut. It can also achieve optimization on certain jobs, like comparing different production plans and well placement strategies. Since the model is built purely based on geological data, its quality varies depending on how well the regional geology is captured and understood, and this can also be a limitation of the reservoir model <ref name=":2" /><ref>Sambo, C., Iferobia, C. C., Babasafari, A. A., Rezaei, S., & Akanni, O. A. (2020). The Role of Time Lapse(4D) Seismic Technology as Reservoir Monitoring and Surveillance Tool: A Comprehensive Review. ''Journal of Natural Gas Science and Engineering'', ''80'', 103312. <nowiki>https://doi.org/10.1016/j.jngse.2020.103312</nowiki></ref>.

Since there are many different types of reservoirs, extraction methods have also been developed differently to achieve efficient production for each case. And they can be separated under two main reservoir types: conventional and unconventional.
{| class="wikitable"
|+
!Reservoir Type
!Geological Characteristics
!Main Extraction Methods
!Engineering
Reason
|-
|Conventional reservoirs
|High permeability and porosity for fluids to flow naturally toward the well through connected pore spaces
|Primary production relies on natural reservoir pressure and secondary recovery methods like water injection are used to maintain the pressure
|Maintain and increase reservoir pressure to improve flow toward production wells
|-
|Unconventional reservoirs
|Low permeability so fluids are trapped in rocks or exist as highly viscous bitumen
|Horizontal drilling and hydraulic fracturing are commonly used for shale gas and tight oil
For deep oil sands, steam-assisted gravity drainage can be used by injecting steam underground to heat bitumen and lower the viscousity
|Create flow pathways to make hydrocarbons mobile enough to be produced
|}
Overall, geology has a strong influence on engineering decisions in oil and gas extraction. Geology informs engineers to know the reservoir quality, what extraction methodology can be applied, and what risks might exist during production. Geological information has also been integrated into reservoir models to provide a more in-depth understanding and optimization. Oil extraction is not just about improving equipment and technology, it is also a process in which geological knowledge is applied with engineering decisions.

=== Chemical Engineering and Petroleum Products ===

=== Environmental issues ===
[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Conclusion / Your Evaluation of the Connections==

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/Projects

2026-06-11T02:17:50Z

KemingWu: /* Project Table */

{{Start tab|
| tab-1 = Project Guidelines
| link-1 = Course:EOSC311
| tab-3 = Create Your Wiki Page
| link-3 = Course:EOSC311/Projects
| tab-4 = Past Projects
| link-4 = Course:EOSC311/Past_Projects
| tab-5 = Help and Resources
| link-5 = Course:EOSC311/Help and Resources
}}
{{Infobox_EOSC311}}

==Create Your Wiki Page==
We have made it easy for you to create your assignment page right from here. Just '''add the title of your project to the box below and click on the create page''' button (note that you will need to be logged in to the UBC Wiki in order for this to work). On the edit screen that loads, add your name to the edit screen and hit '''SAVE''' at the bottom of the page. You can delete this later when you are ready to start writing your article.
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==Project Table==
After you have created your project page, please add your information to the project below. You can edit the table by double clicking on the table.

{| class="wikitable sortable" width="100%"
|+
|-
!! style="width:5%"|Project No.
! style="width: 10%"|'''Your Faculty'''
! style="width: 20%"|'''Your Majors'''
!'''Project'''
|-
|01
|Education
|Master of Educational Technology
|[[Course:EOSC311/2026/demo project|Sample Project]]
|-
|02
|Science
|Computer Science
|[[Course:EOSC311/2026/AI-Powered Geological Mapping|AI-Powered Geological Mapping]]
|-
|03
|Arts
|ANTH, FNEL & HIST
|[[Course:EOSC311/2026/Rock Formations: The Longest Historic Textbook|Rock Formations: The Longest Historic Textbook]]
|-
|04
|Science
|BIOC
|[[Course:EOSC311/2026/Stromatolites: Biochemical Contributions to Early Geological Formations|Stromatolites: Biochemical Contributions to Early Geological Formations]]
|-
|05
|Science, Commerce
|Math, Accounting
|[[Course:EOSC311/2026/The Economic Impact of Geological Natural Disasters|The Economic Impact of Geological Natural Disasters]]
|-
|06
|Science, Engineering
|Computer Science, Electrical Engineering
|[[Course:EOSC311/2026/Applications of Graph Theory in Geology|Applications of Graph Theory in Geology]]
|-
|07
|Science
|Biology
|[https://wiki.ubc.ca/index.php?veaction=edit&preload=Course%3AEOSC311%2FTemplate&title=Course%3AEOSC311%2F2026%2FPrimary+Succession+on+New+Volcanic+Terrain&create=Create+page&redirect=no Primary Succession on New Volcanic Terrain]
|-
|08
|Science
|Computer Science
|[[Course:EOSC311/2026/The Impact of Key Computing Advancements on Resource Extraction|The Impact of Key Computing Advancements on Resource Extraction]]
|-
|09
|Science
|Computer Science
|[[Course:EOSC311/2026/From Rocks to RAM: The Geological Foundation of Computer Boards|From Rocks to RAM: The Geological Foundation of Computer Boards]]
|-
|10
|Science
|STATS, MICB &
|[[Course:EOSC311/2026/Volcanic Ash Composition and its effects on Human Health and Microbial Ecosystems|Volcanic Ash Composition and its effects on Human Health and Microbial Ecosystem]]
|-
|11
|Science
|Chemistry, Chemical Biology
|[https://wiki.ubc.ca/Course:EOSC311/2026/Hyperspectral_Imaging Hyperspectral Imaging]
|-
|12
|Science, Engineering
|Chemistry, Chemical Engineering, CMS
|[https://wiki.ubc.ca/Course:EOSC311/2026/Geological_Resources:_Oil_and_Gas Geological Resources: Oil and Gas]
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==Project List (auto generated)==
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namespace=Course
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==Project Template==
*[[Course:EOSC311/Template|Template]]

Course:EOSC311/2026/Geological Resources: Oil and Gas

2026-06-11T02:11:48Z

KemingWu: Created page

Add Summary Here

==Statement of connection and why you chose it==

==Main text==
[[File:Canada British Columbia location map Okanagan.svg|thumb|Map Example]]

==Conclusion / Your Evaluation of the Connections==

==References==
<references />

{{Projectbox_EOSC311}}
[[Category:EOSC311]]

Course:EOSC311/Projects

2026-06-11T02:00:18Z

KemingWu: /* Project Table */

{{Start tab|
| tab-1 = Project Guidelines
| link-1 = Course:EOSC311
| tab-3 = Create Your Wiki Page
| link-3 = Course:EOSC311/Projects
| tab-4 = Past Projects
| link-4 = Course:EOSC311/Past_Projects
| tab-5 = Help and Resources
| link-5 = Course:EOSC311/Help and Resources
}}
{{Infobox_EOSC311}}

==Create Your Wiki Page==
We have made it easy for you to create your assignment page right from here. Just '''add the title of your project to the box below and click on the create page''' button (note that you will need to be logged in to the UBC Wiki in order for this to work). On the edit screen that loads, add your name to the edit screen and hit '''SAVE''' at the bottom of the page. You can delete this later when you are ready to start writing your article.
<inputbox>
useve=yes
placeholder=project title here
preload=Course:EOSC311/Template
prefix=Course:EOSC311/2026/
type=create
allowcachedresults=false
</inputbox>

==Project Table==
After you have created your project page, please add your information to the project below. You can edit the table by double clicking on the table.

{| class="wikitable sortable" width="100%"
|+
|-
!! style="width:5%"|Project No.
! style="width: 10%"|'''Your Faculty'''
! style="width: 20%"|'''Your Majors'''
!'''Project'''
|-
|01
|Education
|Master of Educational Technology
|[[Course:EOSC311/2026/demo project|Sample Project]]
|-
|02
|Science
|Computer Science
|[[Course:EOSC311/2026/AI-Powered Geological Mapping|AI-Powered Geological Mapping]]
|-
|03
|Arts
|ANTH, FNEL & HIST
|[[Course:EOSC311/2026/Rock Formations: The Longest Historic Textbook|Rock Formations: The Longest Historic Textbook]]
|-
|04
|Science
|BIOC
|[[Course:EOSC311/2026/Stromatolites: Biochemical Contributions to Early Geological Formations|Stromatolites: Biochemical Contributions to Early Geological Formations]]
|-
|05
|Science, Commerce
|Math, Accounting
|[[Course:EOSC311/2026/The Economic Impact of Geological Natural Disasters|The Economic Impact of Geological Natural Disasters]]
|-
|06
|Science, Engineering
|Computer Science, Electrical Engineering
|[[Course:EOSC311/2026/Applications of Graph Theory in Geology|Applications of Graph Theory in Geology]]
|-
|07
|Science
|Biology
|[https://wiki.ubc.ca/index.php?veaction=edit&preload=Course%3AEOSC311%2FTemplate&title=Course%3AEOSC311%2F2026%2FPrimary+Succession+on+New+Volcanic+Terrain&create=Create+page&redirect=no Primary Succession on New Volcanic Terrain]
|-
|08
|Science
|Computer Science
|[[Course:EOSC311/2026/The Impact of Key Computing Advancements on Resource Extraction|The Impact of Key Computing Advancements on Resource Extraction]]
|-
|09
|Science
|Computer Science
|[[Course:EOSC311/2026/From Rocks to RAM: The Geological Foundation of Computer Boards|From Rocks to RAM: The Geological Foundation of Computer Boards]]
|-
|10
|Science
|STATS, MICB &
|[[Course:EOSC311/2026/Volcanic Ash Composition and its effects on Human Health and Microbial Ecosystems|Volcanic Ash Composition and its effects on Human Health and Microbial Ecosystem]]
|-
|11
|Science
|Chemistry, Chemical Biology
|[https://wiki.ubc.ca/Course:EOSC311/2026/Hyperspectral_Imaging Hyperspectral Imaging]
|-
|12
|Science, Engineering
|
|[https://wiki.ubc.ca/Course:EOSC311/2026/Geology_and_Energy_Resource_Extraction:_Group_M Geology and Energy Resource Extraction: Group M]
|-
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|21
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|-
|}

==Project List (auto generated)==
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==Project Template==
*[[Course:EOSC311/Template|Template]]

Course:EOSC311/2026/Geology and Energy Resource Extraction: Group M

2026-06-11T01:56:03Z

KemingWu: Created page

Course:VANT149/2023/Capstone/Science/Team3

2023-07-10T15:22:08Z

KemingWu: /* The Influence of the Moon Movement to the Tides at the Wreck Beach */

== Title ==

==Abstract==

==Biographies==
[[Category:Vantage College Capstone Conference]]
[[Category:Vantage College Science]]

Course:VANT149/2023/Capstone/Science/Team11

2023-07-10T15:21:28Z

KemingWu: /* The Moon Movement And Tides */

== The Influence of the Moon Movement to the Tides at the Wreck Beach ==

==Abstract==
As the closest planet to the Earth, the movement of the Moon has a crucial influence on the variation of the Earth's tides. This experiment was an attempt to study the direct relationship between the Moon's positions and the tides. Specifically, data was collected on the 24-hour variation of the moon and the 24-hour variation of the tides for four days in the month of May (1st, 10th, 20th, 30th). The relationship between the two of them was then analyzed by comparing the charts of moon's altitude vs. time and tides vs. time. The results of this study surprisingly showed no direct connection between daily moon movements and tides. This study indicates that although the moon is the closest to the earth, the moon's movements is not the only major factor that affects tides. Tidal variations might also relate to the shape of the Earth, the depth of the oceans, and the movement of the sun.

==Biographies==
Keming Wu (Coco) is interested in physics, especially gravitational force and their influences. She is working on the methods that support the study and the discussion that analysis the results of the experiments.

Yutong Shi (Crystal) is interested in mathematics and data analysis. She focused on collecting the data and analyzing those data by visualization (comparing the movements of the moon with the change of tides).
[[Category:Vantage College Capstone Conference]]
[[Category:Vantage College Science]]

Course:VANT149/2023/Capstone/Science/Team3

2023-07-10T13:23:01Z

KemingWu: /* Abstract */

== The Influence of the Moon Movement to the Tides at the Wreck Beach ==

==Abstract==

As the closest planet to the Earth, the movement of the Moon has a crucial influence on the variation of the Earth's tides. This experiment is an attempt to study the direct relationship between the Moon's positions and the tides. Specifically, data was collected on the 24-hour variation of the moon and the 24-hour variation of the tides for four days in the month of May. The relationship between the two of them was then analyzed by comparing the charts of moon's altitude vs. time and tides vs. time. The results of this study surprisingly showed no direct connection between daily moon movements and tides. This study indicates that although the moon is the closest to the earth, the moon's movements is not the only major factor that affects tides. Tidal variations are also related to the shape of the Earth, the depth of the oceans, and the movement of the sun.
==Biographies==
Keming Wu (Coco) is interested in physics, especially gravitational force and their influences. She is working on the methods that support the study and the discussion that analysis the results of the experiments.

Yutong Shi (Crystal) is interested in mathematics and data analysis. She focused on collecting the data and analyzing those data by visualization (comparing the movements of the moon with the change of tides).
[[Category:Vantage College Capstone Conference]]
[[Category:Vantage College Science]]

Course:VANT149/2023/Capstone/Science/Team3

2023-07-10T13:19:56Z

KemingWu: /* Biographies */

== The Influence of the Moon Movement to the Tides at the Wreck Beach ==

==Abstract==

As the closest planet to Earth, the movement of the Moon has a crucial influence on the variation of the Earth's tides. This experiment is an attempt to study the direct relationship between the Moon's positions and the tides. Specifically, data was collected on the 24-hour variation of the moon and the 24-hour variation of the tides for four days in the month of May. The relationship between the two of them was then analyzed by comparing the charts of moon's altitude vs. time and tides vs. time. The results of this study surprisingly showed no direct connection between daily moon movements and tides. This study indicates that although the moon is the closest to the earth, the moon's movements is not the only major factor that affects tides. Tidal variations are also related to the shape of the Earth, the depth of the oceans, and the movement of the sun.
==Biographies==
Keming Wu (Coco) is interested in physics, especially gravitational force and their influences. She is working on the methods that support the study and the discussion that analysis the results of the experiments.

Yutong Shi (Crystal) is interested in mathematics and data analysis. She focused on collecting the data and analyzing those data by visualization (comparing the movements of the moon with the change of tides).
[[Category:Vantage College Capstone Conference]]
[[Category:Vantage College Science]]

Course:VANT149/2023/Capstone/Science/Team3

2023-07-10T13:08:05Z

KemingWu: /* Abstract */

== The Influence of the Moon Movement to the Tides at the Wreck Beach ==

==Abstract==

As the closest planet to Earth, the movement of the Moon has a crucial influence on the variation of the Earth's tides. This experiment is an attempt to study the direct relationship between the Moon's positions and the tides. Specifically, data was collected on the 24-hour variation of the moon and the 24-hour variation of the tides for four days in the month of May. The relationship between the two of them was then analyzed by comparing the charts of moon's altitude vs. time and tides vs. time. The results of this study surprisingly showed no direct connection between daily moon movements and tides. This study indicates that although the moon is the closest to the earth, the moon's movements is not the only major factor that affects tides. Tidal variations are also related to the shape of the Earth, the depth of the oceans, and the movement of the sun.
==Biographies==
[[Category:Vantage College Capstone Conference]]
[[Category:Vantage College Science]]

Course:VANT149/2023/Capstone/Science/Team3

2023-07-10T12:36:35Z

KemingWu: /* Replace this text with your project title */

== The Influence of the Moon Movement to the Tides at the Wreck Beach ==

==Abstract==

==Biographies==
[[Category:Vantage College Capstone Conference]]
[[Category:Vantage College Science]]