THE PETROLEUM SYSTEM AS A WORKING HYPOTHESIS

A petroleum system investigation starts with a working hypothesis for generation, migration, and entrapment of petroleum in a province, based on
available geological and geochemical data, which evolves as more data becomes available (Fig. 2A, B). The investigator starts with an oil and gas field map and related field data for the petroleum province of interest. The geographic location of the accumula­tions is important because accumulations located close together are more likely to have originated from the same pod of active source rock (Fig. 4). Accumulations that occur in the same or nearly the same stratigraphic interval are also likely to be from the same active source rock. In contrast, accumula­tions separated by barren rock sections are presumed to have originated from different pods of active source rock. Accumulations of widely differing bulk properties, such as gas versus oil, API oil gravity, gas- to-oil ratios, and sulfur contents, may also be presumed to originate from different pods of active source rock. Detailed geochemical data on oil and gas samples provide the next level of evidence for determining whether a series of hydrocarbon accu­mulations originated from one or more pods of active source rock. Last, comparing the geochemistry of oils and gases to possible source rocks provides the highest level of certainty as to which active source rock generated which oil or gas type.

By acquiring and organizing information that addresses these issues of location, stratigraphic position, and geochemistry, an investigator can take a working hypothesis of how a particular petroleum system formed to increasing levels of certainty (Fig. 2; Table I). The investigator organizes the

information on the oil and gas accumulations into groups of like petroleum types on the oil and gas field map, cross section and table (Figs. 2A, 2B, and 2C).

With this step completed, the investigator then locates all surface seeps on the oil and gas field map, which now becomes the petroleum system map. The seeps with the same geochemical composition as the subsurface accumulation provides geographic evidence for the end point of a migration path. The strati­graphic unit from which the fluid emanates can be compared to the stratigraphic unit in which oil and gas accumulations are found to determine the complexity of their migration paths. If the stratigraphic units are the same, then the migration paths are simple. If they are different, migration may be more complex. Geochemical information from seeps can be compared with that of discovered accumulations in order to link the seep fluid to the proper petroleum system.

Oil and gas shows in exploratory wells are added to the petroleum system map and cross section to better define the migration paths. As this map and cross section evolve, the investigator is encouraged to anticipate how the final map will look based on the framework geology and petroleum fluid information. Intuitively, exploration risk is high if the petroleum system is complicated and hence less predictable; risk is lower if the petroleum system is simple and thus more predictable.

After similar hydrocarbon fluids in the petroleum system have been mapped individual oil and gas accumulations are tabulated to better understand the size (by volume) and complexity of the petroleum system. The petroleum system table is organized by stratigraphic interval in each field (Fig. 2C). These stratigraphic intervals are zones, members, and formations that produce or contain measurable amounts of oil and gas. The table should include age of the stratigraphic interval, API gravity and sulfur content of the oil, gas-to-oil ratio (GOR), cumulative amount of oil and gas produced, and the remaining amount of oil and gas that can be produced. Other information the investigator may chose to include are lithology, gross and net thickness, porosity and permeability of the reservoir rock, geometry, closure, and area of the trap, and detailed geochemistry of the oil and gas. The information included in the table will depend on what is available and the objectives of the investiga­tion. The required information is used to determine the size (by volume) of the petroleum system, which reservoir rock name is to be used in the name of the petroleum system, and to evaluate the complexity of the migration path.

Now the provenance or origin of the petroleum is mapped as the pod of active source rock. Only one pod of active source rock occurs in each petroleum system. A pod is a contiguous body of source rock that has or is expelling oil and gas. Because this pod has thickness and area, it can be mapped using well, outcrop, or geophysical data. When an organic-rich rock is in close, or reasonably close, proximity, both stratigraphically and geographically, to oil and gas accumulations, shows, or seeps, it is tentatively correlated with those fluids. Based on seismic, well, or outcrop data, the likelihood of correlation increases when the source rock’s burial depth is known to reach 3 km, which in the experience of the authors is a reasonable minimum burial depth for thermal maturity or when burial depth modeling indicates a source rock is in of below the oil window. The correlation gains certainty if the source rock, by vitrinite reflectance or some other analytical techni­que, is established as being thermally mature. If the kerogen type of the source rock is consistent with that of the oil and gas, then confidence increases that the source rock is correctly correlated. If the geochemical composition of the organic matter in the source rock compares favorably with the migrated petroleum, the oil-source rock correlation is considered a match. Using seismic, well, and outcrop data, the suspected or confirmed active source rock is mapped as a contiguous, three-dimensional body, or pod, on the petroleum system map and cross section.

In this manner, the petroleum system map and cross section evolve, as the working hypothesis is taken to successive level of certainty. To further refine this work, a burial history chart and events chart are constructed and the petroleum system is named. This article discussed each of these petroleum system components in sequence, but they are frequently developed in parallel, and their relationship to each other is considered so that the petroleum system can be properly mapped. To organize these components, the petroleum system folio sheet is used.

[1] Unit Operations

[2] Systems

[3] Federal tax policies/fees: impacts of energy tax policies on the economy and energy system; impacts of Btu or carbon taxes; revenue recycling options (how portions of taxes are recycled through the

[4] The load and demand-side management (LDSM) submodule processes electricity demand to construct load curves.

• The electricity capacity planning (ECP) submo­dule projects the construction of new utility and nonutility plants, the level of firm power trades, and the addition of scrubbers for environmental com­pliance.

• The electricity fuel dispatch (EFD) submodule dispatches the available generating units, both utility and nonutility, allowing surplus capacity in select regions to be dispatched for another region’s needs (economy trade).

• The electricity finance and pricing (EFP) sub­module calculates total revenue requirements for each operation and computes average and marginal cost-based electricity prices.

[5] The overall cost for Canada of achieving the Kyoto target is very sensitive to the price of carbon rights, but it is much less sensitive to the case considered. For instance, for the high carbon price,

[6] Resource Estimates for Unconventional Gas

[7] Identification and articulation of needs and concerns that are being overlooked, or that are not receiving sufficient attention, by the state and the market

• Research and analysis to examine specific issues as well as potential solutions

• Advocacy, information, and technical assistance provision (e. g., coalition building) to citizens, policymakers, politicians, media, NGOs, and other groups

• Agenda setting

• Policy development

• Policy change and alternative policy formulation

• Policy implementation

[8] Introduction

[9] The Fusion Reactor

[10] Conclusion

Glossary

International Thermonuclear Experimental Reactor (ITER) Project whose main goal is to demonstrate the scientific and technological feasibility of fusion energy for peaceful purposes; ITER will study burning plasmas (i. e., plasmas where heating is provided mainly by the alpha particles created from fusion reactions) and will also be the first machine incorporating most of the technologies crucial for the preparation of a future fusion reactor (e. g., plasma facing components, tritium management, robotics, tests of breeding blankets). Joint European Torus (JET) Flagship of the European Community Fusion Program; JET is the largest and most powerful fusion experiment in the world. keV Abbreviation for kiloelectronvolt; in nuclear physics, energy is often expressed in electronvolts and multiples thereof; as a result of popular misuse of language, temperature is sometimes also indicated in kiloelectron – volts.

At the core of the sun and stars, light nuclei combine—or fuse—to create heavier nuclei. This process releases a significant quantity of energy and is the source of the heat and light that we receive. Our sun has been shining for more than 4 billion years, and according to astrophysics, it will shine for this long again before entering the phase that will lead to its extinction. Harnessing this type of reaction on Earth for the purpose of generating energy would open the way to nearly unlimited resources. This is the aim of fusion research undertaken by the leading industrial nations. After a reminder of the main

[11] Radionuclides in Nuclear Waste

[12] The Low-Level Radioactive Waste Policy Act of 1980 requires each state to be responsible for disposing of LLW generated within its borders, either by providing a suitable disposal site or by entering into compacts with other states to develop a shared site. The disposal sites were to be in operation by 1986.

• The Nuclear Waste Policy Act (NWPA) of 1982 created the Office of Civilian Radioactive Waste Management in the DOE and gave it the responsi­bility for developing a system to manage SNF and HLW. The act also directed the secretary of energy to

[13] Force acting downward on a rock-cutting tool called a drill bit

Carry out a reconnaissance survey.

[15] Finalize the route through a detailed survey.

The following paragraphs describe each factor and subfactor.

[16] Reducing subjectivity in the decision making process when selecting an inspection technique

• Identifying the right pipeline or segment for inspection and maintenance

• Formulating an inspection and maintenance policy

[17] Relative Abundance of the Elements

[18] Energy: Redox Reactions, Thioesters, and Phosphate

[19] Gibbs Free Energies of Formation

[20] Peat as an Energy Source

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