THE USE OF U.S. GEOLOGICAL SURVEY CD-ROM-BASED PETROLEUM ASSESSMENTS IN UNDERGRADUATE GEOLOGY LABORATORIES

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1 THE USE OF U.S. GEOLOGICAL SURVEY CD-ROM-BASED PETROLEUM ASSESSMENTS IN UNDERGRADUATE GEOLOGY LABORATORIES Robert L. Eves Division of Geosciences, Southern Utah University, Cedar City, UT 84720, Larry E. Davis Department of Biology, College of St. Benedict, St. John s University, Collegeville, MN , ldavis@csbsju.edu Thaddeus S. Dyman U. S. Geological Survey, Energy Resources Team, Denver Federal Center Box 25046, MS 939, Denver, CO , dyman@usgs.gov Kenneth I. Takahashi U. S. Geological Survey, Energy Resources Team, Denver Federal Center, Box 25046, MS 939 Denver, CO , kt@usgs.gov ABSTRACT Domestic oil production is declining and United States reliance on imported oil is increasing. America will be faced with difficult decisions that address the strategic, economic, and political consequences of its energy resources shortage. The geologically literate undergraduate student needs to be aware of current and future United States energy issues. The U.S. Geological Survey periodically provides energy assessment data via digitally-formatted CD-ROM publications. These publications are free to the public, and are well suited for use in undergraduate geology curricula. The U.S. Geological Survey (USGS) 1995 National Assessment of United States Oil and Gas Resources (Digital Data Series or DDS-30) (Gautier and others, 1996) is an excellent resource for introducing students to the strategies of hydrocarbon exploration and for developing skills in problem-solving and evaluating real data. This paper introduces the reader to DDS-30, summarizes the essential terminology and methodology of hydrocarbon assessment, and offers examples of exercises or questions that might be used in the introductory classroom. The USGS contact point for obtaining DDS-30 and other digital assessment volumes is also provided. Completing the sample exercises in this report requires a copy of DDS-30. Keywords: economic geology energy sources; education computer assisted; education geoscience; education laboratory; education undergraduate; geoscience teaching and curriculum INTRODUCTION The United States is strongly dependent on fossil fuels-coal, oil, and natural gas-for its energy needs. In any discussion of fossil fuels, several important questions arise: (1) How much is left? (2) How long will reserves last? (3) Where are the remaining undiscovered resources located? (4) What are the geological, economic, and environmental implications associated with the availability of these resources? A resource refers to the amount of a given energy-producing material that may eventually become available for use. Reserves are resources that are already discovered that can be economically recovered. Undiscovered resources are postulated by geologists to exist outside of known fields based on geologic information and theory. Refer to the Appendix for explanations of these and other terms used in this report. It is useful for undergraduate students to understand the nature of undiscovered oil and gas resources, where these resources are inferred to exist, the volumes of undiscovered oil and gas, and the geologic controls governing these resources. Using oil and gas exploration as an introduction to economic geology is a long-standing geological tradition (Wheeler, 1975, and Fisher, 1977). As computer availability for undergraduates has increased, oil and gas exploration games and activities have proliferated (Nichols, 1985; Searight, 1985; and Burger, 1989). Student use of computers in geoscience education seems to have a serendipitous effect. Merrits and Shane (1992) reported that because students enjoyed using computers in an environmental geology class, they readily grasped interactively presented concepts, even when the concepts were challenging. Students retain this information at least as well as when it was presented to them orally or in reading assignments. Oil and gas exploration strategies offer new approaches to energy curricula. Use of real oil and gas exploration data applications encourages critical thinking and higher order learning. During basin analysis laboratory exercises, Soreghan and Soreghan (1999) determined that students were able to learn to analyze disparate datasets, construct working hypotheses, and formulate conclusions and/or specific recommendations. The purpose of this paper is to introduce faculty and students to the U.S. Geological Survey (USGS) 1995 National Assessment of United States Oil and Gas Resources Results, Methodology, and Supporting Data (Gautier and others, 1996), published as a USGS Digital Data Series report (DDS-30), and to summarize the potential it provides for learning opportunities in petroleum geology laboratory exercises. This paper also offers a brief introduction to other USGS digital products, including those dealing with coal and world en- 312 Journal of Geoscience Education, v.50, n.3, May, 2002, p

2 For an assessment of America s petroleum endowment in Federal offshore waters, see U.S. Minerals Management Service (1996). The estimates presented are intended to capture the range of uncertainty, to provide indicators of the relative potential of different petroleum provinces, and to present a useful guide in considering possible effects of future oil- and gas-related activities within the United States. The commodities considered were crude oil, natural gas, and natural gas liquids (NGL) that are producible from the subsurface through a well. METHODOLOGY OF USGS 1995 ASSESSMENT Figure 1. Index map of the United States identifying the eight regions for which plays were assessed in the U.S. Geological Survey 1995 National Oil and Gas Assessment. Refer to Gautier and others (1996) for color-enhanced CD-ROM version of this map. ergy assessments. Using the information and data provided in DDS-30 in a laboratory exercise, students should be able to develop the skills necessary to create an exploration strategy for petroleum basins, solve complex geologic problems, and evaluate data sets. Questions which can be posed include: (1) Where are the best source and reservoir rocks? (2) At what depths should wells penetrate these rocks? (3) What traps and seals are required for the accumulation of oil and gas? Students will require a basic understanding of petroleum geology (see glossary of terminology in the Appendix) and a basic knowledge of probability theory and elementary statistics. OVERVIEW OF THE 1995 USGS NATIONAL OIL AND GAS ASSESSMENT The purpose of the 1995 National Oil and Gas Resource Assessment was to develop a set of scientifically-based hypotheses concerning the technically-recoverable quantities of oil and gas that could be added to the reserves of the United States (Gautier and others, 1996). This assessment does not predict at what time, or what part of potential resources will be added to reserves. Resources are evaluated regardless of political, economic, and other considerations (USGS National Oil and Gas Resource Assessment Team, 1995). A parallel study was conducted to determine the economically-recoverable resources described in the 1995 assessment (Attanasi, 1998). Onshore and State-owned offshore areas of the United States were divided into eight regions, consisting of 71 provinces, within which 560 plays were assessed. The 1995 USGS National Petroleum Assessment was based on the play concept, in which a play is defined as a set of geologically similar discovered and undiscovered accumulations of oil and (or) gas (Gautier and others, 1996). A play is not a single drillable prospect, but includes several prospects with similar geologic characteristics. It may have an exploration potential for conventional or unconventional accumulations and may be considered either as hypothetical (for the 1995 assessment, no known discovery history of fields greater than 1 million barrels of oil (MMBO) or 6 billion cubic feet of gas (BCFG)) or as confirmed (known discovered accumulations greater than 1 MMBO or 6 BCFG). Confirmed plays were analyzed using field-size distributions, numbers of known accumulations, depths to production, and other geologic and production factors. Hypothetical plays were analyzed by using geologic analogs based on other provinces or by using simulation models based on geological, geophysical, and geochemical data. Hypothetical plays were risked if some uncertainty existed as to the existence of at least one 1-MMBO or 6-BCFG undiscovered accumulation. In the assessment of conventional plays, a Truncated Shifted Pareto (TSP) distribution was used to model the size-frequency distribution of the population of oil and gas accumulations (Houghton and others, 1993). TSP data were combined with available geologic and production data in order to develop hypotheses about undiscovered conventional accumulations within a play and to estimate the sizes and numbers of accumulations remaining to be discovered for each play. The sizes and numbers of undiscovered accumulations were subjected to Monte Carlo simulation using play probability and other data to calculate a range of resources. Play-level assessments were subjected to review and compiled into provincial, regional, and National totals (Gautier and others, 1996). Small, undiscovered, accumulations (< 1 MMBO or 6 BCF) in conventional plays were treated separately for the 1995 assessment, based on extrapolations of numbers of field size classes greater than 1 MMBO or 6 BCF (Root and Attanasi, 1993). This estimate was made at the province level only. Eves et al. - Use of the USGS Petroleum Assesments in Geology Laboratories 313

3 success ratio, number of untested cells, and EUR probability distribution yielded potential undiscovered resources for each play (Schmoker, 1996; Schmoker and Dyman, 1997). New USGS National Oil and Gas National Assessment (NOGA) A different methodology is being used by the USGS in currently reassessing undiscovered conventional oil and gas resources in 25 priority provinces of the United States having the potential to be added to reserves within the next thirty years. This new assessment uses a probabilistic total petroleum system and assessment unit approach. Estimates of undiscovered oil and gas resources that were published in DDS-30 are considered ultimate in that they could be developed far into the future. The new NOGA assessment only considers undiscovered resources that will be added to reserves in the foreseeable future (the next 30 years). Resource estimates for priority provinces are not yet available. Figure 2. Exploration History Map of the Denver Basin illustrating the development of drilling through time. Refer to Gautier and others for explanation of the data used in compiling this map. Because of uncertainties in estimating undiscovered accumulations of oil and gas, estimates were presented as a range of values associated with different probabilities of occurrence for each play. A pessimistic case has at least a 95-percent chance of occurrence, an optimistic case has at least a 5-percent chance of occurrence, and a mean case represents the arithmetic average of all possible outcomes, weighted by their probability. Continuous-type plays were treated as a separate category in the 1995 National Petroleum Assessment and were assessed using a specialized methodology developed by the USGS (Schmoker, 1996). These continuous-type plays are geologically diverse and fall into the following categories: coalbed gas, biogenic gas, fractured shale gas, and basin-center gas. The assessment of continuous-type plays is based on the concept that each accumulation can be regarded as a collection of hydrocarbon-bearing cells. In the play, cells represent spatial subdivisions defined by the drainage area of wells. Cells may be productive, nonproductive, or untested. Geologic risk, expressed as play probability, was assigned to each play. The number of untested cells in a play and the fraction of untested cells expected to become productive (success ratio) were estimated, and a probability distribution was defined for estimated ultimate recovery (EUR) for those cells expected to become productive. The combination of play probability, Getting Acquainted with the Basic Information of DDS-30 Ideas for Laboratory Exercises - DDS-30 can be used on either Macintosh or PC-Windows microcomputers. For Windows systems, insert the CD-ROM and double click on the 95assess.exe icon. For Macintosh users, double click on the 95assess.mac icon. Follow instructions for each screen as directories indicate. What follows represents a typical series of exercises utilizing DDS-30 for students in an introductory geology laboratory. Other basins and regions can be examined, and a myriad of other questions asked. The depth and rigor of the questions can be adjusted according to the instructor s wishes and student background and/or knowledge. Exercise 1- Introduction Screen 1 USGS/Department of the Interior Logo (click) Screen 2 Title page (click) Screen 3 Editor page (click) Screen 4 Main Menu Index map **(click) Table of Contents Credits Quit **This index map identifies the eight regions for which plays were assessed in this report (figure 1). By clicking on a region name, a map of the contained provinces appears. From the region map, clicking on U. S. Exploration History, and then clicking on Start, provides a graphical representation of the development of United States oil and gas exploration in 5-year increments from You can also look at the exploration history by clicking on the arrows. The dots are cells (2 mi 2 in 314 Journal of Geoscience Education, v.50, n.3, May, 2002, p

4 Figure 3. Estimated undiscovered oil, natural gas liquids, associated-dissolved gas, and non-associated gas for the confirmed Dakota Group (combined) J and D Sandstones Play (Play 3905) in the Denver Basin (Province 39). F1 through F99 represent fractals of the probability distribution representing the range of resource estimates. For the Dakota Group (Combined J and D Sandstones) play, mean undiscovered oil resources of 61.4 MMBO and mean non-associated gas resources of 21.2 BCFG were estimated. area) that are assigned by colors to the following categories: oil, gas, oil and gas, or dry wells (no production). Please note that users cannot print screens from DDS-30 but can do so using DDS-35, Digital Map, Text, and Graphical Images in Support of the 1995 national Assessment of United States Oil and Gas resources (Beeman and others, 1996). While examining the United States exploration history map, answer the following questions: 1. Where in the United States does most oil, gas, and oil and gas production occur? 2. Why is there no production in the Mid-Continent states, such as Minnesota and Wisconsin? 3. In what region(s) of the United States did the first major petroleum exploration and development occur? Why is this the case? 4.What was the principal hydrocarbon (oil or gas) produced in the early decades of the 20 th century? (oil or gas) Why? When finished with the exploration history map, you must select the Return button to return to the index map. From there, use the Main Menu button (lower left corner) to go back to screen 4, the Main Menu, click on Table of Contents. Screen 5 Table of Contents Executive summary of results Introduction, purpose, and scope Part I Methodology Part II Description of plays assessed (click) Screen 6 Part II Description of plays assessed Introduction Eight regions (click on Region 4) Unconventional plays Screen 7 Region 4 Rocky Mountains and Northern Great Plains Regional report Provinces (click on 39 Denver Basin) Screen 8 Denver Basin Province 39 Eves et al. - Use of the USGS Petroleum Assesments in Geology Laboratories 315

5 Screen 9 Province map (Illustrates location of basin. Click on the red triangle to switch between views of the northern and southern parts of the basins) Province summary Exploration History (click) Province stratigraphy Bibliography Conventional play list Unconventional play list Exploration History Map of the Denver Basin (figure 2; data through 1993). The red line represents the basin outline. Click Start. You may pause at any point by clicking the Pause box. You may also advance or retreat at any time by pressing the red arrows at the base of the map. [Note: The data set is not made up of individual wells, but rather 2 mile 2 cells, which include one or more wells. The cells are represented by variously colored squares based on its dominant well completion characteristics: green (oil), red (gas), blue (both oil and gas) and gray (dry). The map represents the development of these cells through time in 5-year increments based on well completion data for each cell.] EXERCISE 2 - ACCESSING INFORMATION IN A WELLEXPLORED AREA The following questions were selected for the Denver basin, which contains numerous wells and fields. Sample Questions: 1. When and where in the Denver Basin did the first oil production occur? (It mighty be useful to provide students with a geologic map of the basin and a highway map with approximate basin outlines for questions 1-4.) 2. When and where did the first significant gas production occur? 3. What is the current state of exploration and production drilling in the Denver Basin? (poorly, moderately, or well developed) Explain. 4. Identify the areas in the Denver Basin that have been extensively explored, but have not produced oil or gas. (Where are all of the dry holes and cells?) 5. In what five-year increment(s) did major development of oil and gas resources in the Denver Basin take place? 6. Which stratigraphic units are the key gas reservoirs or plays in the Denver Basin? Which are the key oil reservoirs or plays in the Denver Basin? [To answer these questions, return to the first screen in the Denver Basin sequence and examine the stratigraphic relationships by clicking on the Province Stratigraphy button. Then, read the Province Summary section on reservoirs and traps to determine which stratigraphic units are the key reservoirs in the Dakota Group play (play 3905).] 7. Is the Denver Basin a mature reservoir with respect to production? [Note: This could be an opportunity to compare the Denver Basin with another basin that is less mature with respect to drilling.] Return to Denver Basin main screen and click on Conventional Play list. Screen Denver Basin Six conventional plays are identified: plays Click on Dakota Group (Combined J and D Sandstones) play for additional information on the geology and production characteristics of the play, including traps, source rocks, timing and migration, and exploration status (click on red arrows to advance or retreat within the three pages of text about the play). Click on the play map icon to identify the play boundaries and distribution of oil and gas production. (Return) Click on the graphs icon to view numerous graphs of play production characteristics. (Much of this information may be best suited for upper-level geology majors.) (Return) Click on Estimates to identify information on assessment including play attributes; probabilities, sizes and numbers of undiscovered accumulations; ratios of various hydrocarbon types; oil quality; play depth; and on the third page (figure 3), estimates of undiscovered resources by commodity type (e.g. oil, natural gas liquids, associated-dissolved gas, and, non-associated gas). For the Dakota Group (Combined J and D Sandstones) play, mean undiscovered oil resources of 61.4 MMBO and mean non-associated gas resources of 21.2 BCFG were estimated. Questions regarding Dakota Group (Combined J and D Sandstone) Play characteristics. 1. What are the minimum, median, and maximum depths of the play for both oil and gas? 2. This is a confirmed play. Name two producing fields and tell where they are located. 3. Is this play poorly, moderately, or well developed? Explain. 4. Is this play primarily an oil or gas play? What are some of the reasons for your answer? 5. Use the Return button to go back to Screen 7, Region 4 Rocky Mountains and Northern Great Plains. Click on 37 Southwestern Wyoming. Click on Unconventional play list, and click on play 3741 Greater Green River Basin-Mesaverde. Then click on the Estimates button, and determine the mean gas estimate (BCFG) for this play (bottom of third screen). The undiscovered, unconventional resource for the Greater Green River Basin Mesaverde play in the Southwestern Wyoming Province is how much greater than the undiscovered conventional gas re- 316 Journal of Geoscience Education, v.50, n.3, May, 2002, p

6 Conventional play list Kandik Basin summary Screen 13 Exploration History Map of Central Alaska Province (data through 1993). The red line represents the province outline. Click start. You may pause at any point by clicking the Pause box. You may also advance or retreat through time by pressing the red arrows at the base of the map. 1. What is the current state of exploration drilling in the Central Alaska Province? (poorly, moderately, or well developed) Explain. Click the Return button once and go to Screen 12, Central Alaska Province. Click on the Conventional Play list. Figure 4. Index map of Region 1 Alaska illustrating the three provinces. sources of the Dakota Group play in the Denver Basin? 6. We know that the United States currently uses about 22 TCF of gas per year. Assuming that the undiscovered, unconventional Mesaverde gas will ultimately be discovered and produced, how long could it alone sustain the current natural gas energy needs of the Nation? EXERCISE 3- COMPARISON OF A POORLY EXPLORED AREA WITH A HIGHLY PRODUCTIVE AREA The following questions were selected for the Central Alaska province, which contains few wells. Use the Return button to return to the Main Menu screen and click Index Map. Click Alaska. This map illustrates the three provinces that form the Alaska region. Clicking again on Regional Geology will provide a summary of the geology of Alaska. Use the Return button to return to the Index Map of the U.S. and Part II Description of plays assessed. Introduction Eight regions (click on Region1 Alaska) Unconventional plays Screen 11 Region 1 Alaska (figure 4) Regional report Provinces 1-3 (click on 2 Central Alaska) Screen 12 Central Alaska Province map (illustrates location of basins. Click on red triangles to see the rest of the province) Province summary Exploration History (click) Province stratigraphy Bibliography Screen 14 Central Alaska Five conventional plays are identified: plays Click on 201, Central Alaska Cenozoic Gas play for information on the geology and production characteristics of the play, individual reservoir rocks, traps, source rocks, timing and migration, and exploration status. (Click on red arrows to advance or retreat through the text). Click on Estimates to identify information on the assessment including play attributes, probabilities, sizes and numbers of undiscovered accumulations, ratios of various hydrocarbon types and quantities, play depth, and estimates of undiscovered resources by commodity type (e.g. oil, natural gas liquids, associated-dissolved gas, and non-associated gas). For the Central Alaska Cenozoic Gas play, the mean non-associated gas resources were estimated as 2,209.8 BCFG. (See bottom of third screen.) 1. The United States, as a whole, is a mature oil and gas producing country. Based on what you have just learned about the drilling history of Central Alaska, what can be said about this province with respect to drilling maturity? 2. Assuming that the petroleum geology is favorable, can you locate two more frontier areas for United States oil and gas exploration? Not all undeveloped areas are frontier areas. For instance, if you view the exploration history of New England (Region 8, Province 72), it appears to be undeveloped, and thus a frontier area. The New England Province is underlain in part by very old crystalline and metamorphic rocks, and there are no defined plays. This is an example of unfavorable petroleum geology rather than an example of a frontier area.) In contrast to Central Alaska, the onshore and offshore Gulf Coast area of Texas, Louisiana, Mississippi, and Florida is America s premier petroleum-producing region based on current and historic productivity. The region is also estimated to contain a significant portion of the total United States undiscovered, technically-recoverable, conventional oil and gas resources. In Eves et al. - Use of the USGS Petroleum Assesments in Geology Laboratories 317

7 1995, the U. S. Geological Survey estimated a mean resource of billion barrels of technically-recoverable, conventional oil equivalent (BBOE) for the onshore Gulf Coast Region, which is 31 percent of the estimated mean resource of the U. S. (One barrel of oil equals 6,000 cubic feet of gas in energy equivalent units. The TCF of gas in the Gulf Coast region equals 16.3 BBOE. For the Gulf Coast region, sum 5.39 (mean oil in BBO), 16.3 (mean gas in BBOE), and 3.32 (mean natural gas liquids in BBO for a total of BBOE)) 1. What percent of the total Gulf Coast Region undiscovered conventional resource is derived from natural gas in energy equivalent units (BBOE s)? Use the Return button to go to Screen 5, the Table of Contents, and click on the Executive summary of results. Click on Tables, then go to Table 2 for regional estimates of conventional oil and gas resources and Table 4 for unconventional (continuous-type) resources. 2. Identify mean gas resource estimates for each region and convert them to BBOE s, as was done above for the Gulf Coast Region. 3. Based on these estimates and your calculations, what can be said about the availability of future undiscovered, technically-recoverable, conventional oil versus gas resources? According to the data presented in Table 4 of the Executive Summary of DDS-30, the Gulf Coast Region is estimated to contain about 9 TCF (1.5 BBOE) of technically recoverable, continuous-type unconventional gas. 4. Comment on the availability of conventional versus continuous-type unconventional gas resources in the Gulf Coast Region? 5. How does the total undiscovered gas resource of the Southwestern Wyoming Province compare to that of the entire Gulf Coast Region? ADDITIONAL DIGITAL RESOURCES In addition to the 1995 National Assessment of United States Oil and Gas Resources (DDS-30), the USGS has produced other digital reports that can be used as pedagogical tools. One of these is the monumental project, World Petroleum Assessment 2000 Description and Results, DDS-60 (USGS World Energy Assessment Team, 2000) This digital set of four CD-ROMs is the result of a five-year effort to estimate the quantities of conventional oil, gas, and natural gas liquids outside of the United States that have the potential to be added to reserves in the next thirty years. This report places energy resources in a global perspective. In addition to DDS-60, other CD-ROM resources dealing with energy and published by the USGS, present a range of global energy data and assessments. These include: (1) oil and gas resource potential of the Arctic National Wildlife Refuge (Arctic National Wildlife Refuge Assessment Team, 1999), (2) ranking of the world s oil and gas provinces by known petroleum volumes (Klett and others, 1997), and (3) maps showing geology, oil and gas fields, and geologic provinces of the Asia Pacific region (Steinshouer and others, 1999), South America (Schenk and others, 1999), Former Soviet Union (Persits and others, 1998), Arabian Peninsula (Pollastro and others, 1999), South Asia (Wandrey and Law, 1999), and Africa (Persits and others, 1997). Digital coal data products are available, including the National Coal Resource Assessment: 1999 Resource Assessment of Selected Tertiary Coal Beds and Zones in the Northern Rocky Mountains and Great Plains Region (Fort Union Coal Assessment Team, 1999). In this CD-ROM, information regarding the coal beds and zones of the Fort Union Formation and equivalent formations is compiled and assessed. These units have been selected for assessment because the coals are thick, clean, and low in ash and sulfur, and will undoubtedly be the targets of future resource development (Fort Union Coal Assessment Team, 1999). This CD-ROM is one part of the National Coal Resource Assessment Project. The second CD-ROM dealing with the National Coal Resource Assessment has just been released as Professional Paper 1625-B (Kirschbaum and others, 2000). Other National Coal Resource Assessment CD-ROMs will be available from the USGS in the near future. Additional digital data products dealing with energy issues are available through other Federal and State government and research organizations such as the U. S. Department of Energy, U. S. Minerals Management Service, and the Gas Research Institute. The reader can obtain these products by directly contacting these organizations. To obtain copies of USGS digital media (DDS-30, DDS-60, or digital reports), contact USGS Geologic Division, Central Energy Resources Team, Box 25046, Denver Federal Center, MS 939, Denver, Colorado, 80225, or phone ASK-USGS. ACKNOWLEDGEMENTS The authors wish to acknowledge the assistance of the USGS in providing office space, computing facilities, and access to the digital-data-series products during the preparation of this manuscript. We wish to thank James Otton, Steve Condon, Carol Molnia, and Katharine Varnes of the USGS for their helpful reviews of the manuscript. 318 Journal of Geoscience Education, v.50, n.3, May, 2002, p

8 REFERENCES Arctic National Wildlife Refuge Assessment Team, 1999, The oil and gas resource potential of the Arctic National Wildlife Refuge 1002 Area, Alaska, U.S. Geological Survey Open File Report Attanasi, E.D., 1998, Economics and the 1995 national assessment of United States oil and gas resources, U.S. Geological Survey Circular 1145, 36 p. Beeman, W.R., Obuch, R.C., and Brewton, J.D., 1996, Digital map data, text, and graphical images in support of the 1995 national assessment of United States oil and gas resources, U.S. Geological Survey Digital Data Series DDS-35. Burger, R.H., 1989, MacOil an oil exploration simulation, Journal of Geoscience Education, v. 37, p Dyman, T.S., Schmoker, J.W., and Root, D.H., 1996, Assessment of deep conventional and continuous-type (unconventional) natural gas plays in the United States, U.S. Geological Survey Open File Report , 30 p. 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Searight, T.K., 1985, A computer-assisted petroleum exploration and development exercise for undergraduate geology students, Journal of Geoscience Education, v. 33, p Soreghan, G.S. and Soreghan, M.J., 1999, A multi-week basin-analysis lab for sedimentary geology, Journal of Geoscience Education, v. 47, p Steinshouer, D.W., Qiang, J., McCabe, P.J., and Ryder, R.T., 1999, Maps showing geology, oil and gas fields, and geologic provinces of the Asia Pacific region, U.S. Geological Survey Open File Report F. U.S. Geological Survey National Oil and Gas Resource Assessment Team, 1995, 1995 National assessment of United States oil and gas resources, U.S. Geological Survey Circular 1118, 20 p. U.S. Geological Survey World Energy Assessment Team, 2000, U.S. Geological Survey world petroleum assessment 2000 description and results, U.S. Geological Survey Digital Data Series DDS-60, version 1.0. U.S. Minerals Management Service, 1996, An assessment of the undiscovered hydrocarbon potential of the Eves et al. - Use of the USGS Petroleum Assesments in Geology Laboratories 319

9 Nation s outer continental shelf: U.S. Minerals Management Service Resource Evaluation Program, OCS Report, MMS , 40 p. Wandrey, C.J. and Law, B.E., with CD-ROM implementation by Steinshouer, D.W. and Larson, B.S., 1999, Map showing geology, oil and gas fields, and geologic provinces of South Asia, U.S. Geological Survey Open File Report C, version 2. Wheeler, R.R., 1975, The oil game economic geology teaching device, Journal of Geoscience Education, v. 23, p ABOUT THE AUTHORS Robert Eves is an associate professor in the Department of Physical Science at Southern Utah University. He received a B.S. in Geology from Southern Utah University, and M.S. and Ph.D. degrees in Geochemistry from Washington State University. He is currently serving as Head, Division of Geosciences at SUU. Larry Davis is an associate professor in the Department of Biology at the College of St. Benedict St. John s University, where he is Head of the Geology Department. Larry holds a B.A. degree in Marine Biology from Western Washington University, a B.S. in Geology from Boise State University, and M.S. and Ph.D. degrees Geology from Washington State University. Ted Dyman is a geologist and member of the Central Energy Team, USGS. He received B.S. and M.S. degrees in Geology from Northern Illinois University, and holds a Ph. D. in Geology from Washington State University. APPENDIX Glossary of Terminology Accumulation: An oil or gas deposit defined by a trap, charge, and specific reservoir characteristics. May include one or more fields. See Play attributes. Assessment unit: An assessment unit is a volume of rock within a total petroleum system that contains discovered and undiscovered fields that are relatively similar with respect to geology, exploration strategy, and risk characteristics. BCFG-Billion cubic feet of gas and TCFG-Trillion cubic feet of gas: A common means of expressing volumes of natural gas. As a point of reference, the United States currently uses about 22 TCF of natural gas per year. BOE-Barrels of oil equivalent: Gas volume that is expressed in terms of its energy equivalent in barrels of oil. 6,000 cubic feet of gas equals 1 barrel of oil equivalent. Continuous-type accumulation: A hydrocarbon deposit that is pervasive throughout a large area, is not significantly affected by hydrodynamic influences, and for which the standard methodology for assessment of sizes and numbers of discrete accumulations is not appropriate. One or more continuous-type accumulations for a play or assessment unit. Conventional accumulation: A discrete deposit, usually bounded by a downdip water contact, from which oil, gas, or natural gas liquid (NGL) can be extracted using traditional development practices, including production at the surface from a well as a consequence of natural pressure within the subsurface reservoir, artificial lifting of oil from the reservoir to the surface where applicable, and the maintenance of reservoir pressure by means of water or gas injection. Several geologically similar conventional accumulations occur in a conventional play or assessment unit. Cumulative production: That part of the resource already produced. EUR-Estimated ultimate recovery: An estimate of the total future recovery of a well or reservoir based on geologic and engineering data. Field: An individual producing unit consisting of a single pool or multiple pools of hydrocarbons grouped in, or related to, a single structural or stratigraphic feature. Future resources: The sum of reserves and undiscovered resources; they represent those resources still in the ground. GOR-Gas/oil ratio: Average ratio of associated-dissolved gas to oil. An accumulation with a GOR in excess of 20,000 is considered a gas accumulation. Measured in cubic feet of gas per barrel of oil. MMBO-Million barrels of oil: A common unit used in petroleum measurement. Play: A play is a set of known or postulated oil and (or) gas accumulations sharing similar geologic, geographic, and temporal properties, such as source rock, migration pathway, timing, trapping mechanism, and hydrocarbon type. A play may also be referred to as an assessment unit. Plays may be confirmed (contain one or more known accumulations) or hypothetical (no known accumulations). Play attributes: Geologic characteristics that describe principal properties of, and necessary conditions for, the occurrence of oil and (or) gas accumulations of the minimum size (for DDS-30, 1 MMBO [million barrels of oil] or 6 BCFG [billion cubic feet of gas]) within the defined parameters of a play: 1.Charge: The occurrence of conditions of hydrocarbon generation and migration adequate to cause an accumulation of the minimum size. Included in this attribute are subsidiary elements, including existence of source rocks with sufficient organic matter of the appropriate composition, appropriate temperature and duration of heating to generate and ex- 320 Journal of Geoscience Education, v.50, n.3, May, 2002, p

10 pel sufficient quantities of oil and (or) gas, and timing of expulsion of oil and gas from source rocks appropriate for filling available traps. 2.Reservoir: The occurrence of reservoir rocks of sufficient quantity and quality to permit the containment of oil and (or) gas in volumes sufficient for an accumulation of the minimum size. 3.Trap: The occurrence of those structures, stratigraphic pinch-outs, permeability changes, and similar geologic features necessary for the entrapment of oil and (or) gas in at least one accumulation of the minimum size. Play probability: Play probability represents the product of the probabilities of the three play attributes (charge, reservoir, and trap). It is an estimate, expressed as a decimal fraction, of the chance that oil or natural gas exist within the particular play. Reserves: That part of the identified economic resource that is estimated to exist from geologic evidence supported by engineering data. Technically-recoverable resources: Resources in accumulations producible using current recovery technology but without reference to economic profitability. These resources are generally conceived as existing in accumulations of sufficient size to be amenable to the application of existing recovery technology. Total Petroleum System: A total petroleum system is a mappable hydrocarbon-fluid system with all of the essential elements and processes needed for oil and gas accumulations to exist, including source and reservoir rocks, hydrocarbon generation and migration, and traps and seals. Total resources: Resources in our entire Nation s petroleum endowment, including the sum of cumulative production, reserves, and undiscovered resources. Unconventional accumulation: A broad class of hydrocarbon deposits of a type (such as gas in tight sandstones, gas shales, and coal-bed gas) that historically has not been produced using traditional development practices. Undiscovered resources: Resources postulated from geologic information and theory to exist outside of known oil and (or) gas fields. Eves et al. - Use of the USGS Petroleum Assesments in Geology Laboratories 321