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CU.S. and WorId Resources of Hydrocarbons Estimates of U.S. and other countries' primary resources of hydrocar- bons include conventional crude and heavy oils, oil-bearing shales and tar sands, natural gas and natural gas liquids, coal, and biomass. These data represent current estimates of resources available for future exploitation and are expected to change as knowledge of the resources improves. Resources of fossil fuels are typically characterized in physical units in terms such as proved reserves, indicated additional reserves, inferred re- serves, and undiscovered resources, which are defined below. Biomass resources are often expressed in terms of their fuel conversion potential, usually to neat ethanol or methanol. Proved reserves are those quantities of resources for which there is reasonable assurance from geologic, engineer- ing, and other data that the resources are recoverable in future years from known locations under existing economic and operating conditions (EIA, 1989a). Thus, proved reserves are economically recoverable by definition (BEG, 1988~. Indicated additional reserves typically refer to quantities of crude oil judged to be recoverable by enhanced recovery techniques, but where the economic recoverability of the reserves has not been established with sufficient conclusiveness for them to be included under proved re- serves (Considine, 1977~. The term inferred reserves, also referred to as probable resources, is used to denote that part of the identified economic resource base that will be added to proved reserves through extensions, revisions, and new pay zones. Inferred reserves can thus be thought of as resources that reside at the interface of proved reserves and undiscovered resources (BEG, 1988~. As the term implies, undiscovered resources are just that. Their estimates rely on informed judgment but remain speculative until validated by discovery and development. For natural gas three additional categories of the resource base have been 138
APPENDIX C 139 defined. The first category is known as extended reserve growth in nonas- sociated fields onshore. It represents gas distributed in known fields recov- erable through intensive development of heterogeneous reservoirs (i.e., through infill drilling and recompletion of previously bypassed zones). The second category is gas associated with improved recovery (and hence re- serve growth) of mobile of! from known reservoirs. The third category is termed unconventional gas (i.e., gas in low-permeability reservoirs, coal- bed methane, and shale gas). Subject to economic exploitation, these three categories have the potential to increase significantly the proved reserves of U.S. natural gas (BEG, 1988~. U.S. and world resources of conventional crude oil are shown in Tables C-1 and C-2, respectively, and U.S. reserves of natural gas liquids are shown in Table C-3. World reserves are estimated to be in the range of 800 billion bbl, of which about 60 percent is to be found in the Middle East. Eight countries (Saudi Arabia, Iraq, Kuwait, United Arab Emirates, Iran, all in the Middle East, along with the USSR, Venezuela, and Mexico) account for around 80 percent of the reserves, while the United States accounts for about 6 percent. In terms of resources yet to be discovered, it is estimated that the United States has over 10 percent of the world's total. It is be- lieved that the United States is third in original oil endowment (after Saudi Arabia and the USSR) but fifth in remaining oil because over 60 percent of its estimated total recoverable oil (about 230 million bbl) has already been produced (Rive, 1988~. Current annual U.S. consumption of petroleum products is around 6 bil- lion bbl, of which about 40 percent is imported. World consumption is about 22 billion bbVyear (EIA, 1988, l989d). TABLE C-1 U.S. Resources of Crude Oil (billion bbl) Indicated Proved Additional Inferred Undiscovered Reserves Reserves Reserves Resources Lower48 onshore 16.6 3.1 11.2 20.1 Lower48 offshore 3.3 0.1 1.6 12.7 Alaska 7.4 0.6 5.5 16.6 Total 27.3 3.8 18.3 49.4 SOURCE: Kuuskraa et al. (1989~. In this reference, data on proved reserves and indicated additional reserves are attributed to the U.S. Department of Energy, the Energy Information Administration (Annual Report, 1987~; data on inferred reserves and undiscovered resources are attributed to the U.S. Geological Survey's Minerals Management Service (Open-File Report 88-373~.
140 TABLE C-2 World Resources of Crude Oil (billion bbl) APPENDIX C Proved and Indicated Additional Reservesa Oil arid Gas World Journal Oil Proved Reserves, Cong. Res. serv.b Inferred Undis- Reserves, covered 1987 Resources, Total Cong. Res. Cong. Res. Resources, Serv.b Serv.b USGS North 80.7 84.3 59.8 24.4 89.3 139.1-280.5 Africa Middle East Far East America Central and South 65.7 66.9 America Western 22.4 Europe USSR and Eastern Europe 60.8 55.2 33.2 20.1 19.5 61.5 54.2 564.7 470.6 19.2 25.2 9.4 19.3 59.0 51.0 384.5 22.0 11.9 47.5 74.6-135.6 45.1-78.1 77.0 18.5 88.5-158.5 99.0 482.9-619.9 and Oceania 19.4 20.9 36.7 8.1 53.9 41.2-94.2 World Total 868.9 778.5 643.7 142.5 382.2 aEIA (1988, 1989a). The EIA attributes the data on proved and indicated addi- tional reserves to the Oil and Gas Journal, Vol. 82, No. 53 (December 28), 1987, and to World Oil, Vol. 207, No. 2 (August 1988), and the data on total resources to an assessment by the U.S. Geological Survey as of January 1, 1985. As cited by EIA, total resources include inferred reserves and undiscovered resources and are represented with a probability range of 95 to 5 percent. bRiva (198B). Data from 1987. TABLE C-3 U.S. Resources of Natural Gas Liquids (billion bbl) Proved Reserves Inferred Reserves Lower-48 onshore 7.0 4.4 Lower-48 offshore 0.7 0.4 Alaska 0.4 0.2 Total 8.1 5.0 SOURCE: Kuuskraa et al. (1989~.
APPEPID[X C 141 Crude oils with API gravity between 10° and 20° (or with viscosity between 100 and 10,000 cp) are generally considered to be heavy. U.S. and world resources of heavy oil are shown in Tables C-4 and C-5, respectively. They constitute an important but only partly developed resource. Vene- zuela, the Middle East, the United States, and the USSR have 50, 30, 10, and 5 percent of the world's heavy oil, respectively. The majority of the U.S. reservoirs and fields (with over half of the original oil in place) are in California, and there are important deposits in Alaska. The world's produc- tion of heavy oil is estimated at around 1.5 billion bbl/year, or around 7 percent of the world's total crude oil output. In the United States, heavy oil constitutes about 4 percent of total crude production (Rive, 1987~. U.S. and world resources of tar sands are shown in Table C-6. A tar sand (or oil sand) deposit (also known as a bitumen deposit) is defined as a hydrocarbon deposit having an in situ viscosity greater than 10,000 cp at reservoir conditions or an API gravity less than 10°. In cases where a deposit contains bitumen, heavy oil, and lighter oil, the deposit is consid- ered a tar sand if the majority of the hydrocarbon is not mobile at reservoir conditions (Kuuskraa, 1985~. In the United States, tar sand deposits are found in a number of states but the main deposit of about 12 billion bbl is found in Utah with speculative resources in that state amounting to about another 20 billion bbl (IOCC, 1984~. The resource in Alaska of 10 billion bbl is judged to be speculative. Other bitumen resources exist in Alabama, TABLE C-4 U.S. Resources of Heavy Oila (billion bbl) Kunskraa et al. (1989) Riva (1987) Original Oil in Placeb Undis- Total Total Recov- Proved covered erable Reserves Resources Large ReservoirsC Small ReservoirsC Total 80 20 100 34d 18 24 52d aHeavy oil is defined as crude oil with an API gravity of between 10° and 20° or a viscosity between 100 and 10,000 cp. By the same standards, light oil is defined as having an API gravity between 20° and 45°+ or a viscosity between 1- and 100 centipoises (Kuuskraa et al., 1989~. bOriginal oil in place is the estimated gross quantity of oil in a }mown reservoir prior to any production. It is independent of economic and operating considerations governing the recovery of the oil from the reservoir. CTwenty million barrels of original oil in place is used to distinguish large from small reservoirs (Kuuskraa et al., 19891. Includes cumulative production to date of about 10 billion bbl.
142 TABLE C-S World Resources of Heavy Oil (billion bbl) Proved Undiscovered Total Reserves Resources Recoverable North America 23.0 30.1 64.8 Central and South America 279.5 16.2 308.5 Western Europe 8.0 0.2 9.0 USSR and Eastern Europe 7.2 20.6 33.1 Africa 3.6 0.6 4.6 Middle East 115.4 22.1 169.0 Far East and Oceania 12.9 3.6 19.1 World total 449.6 93.4 608.1a aIncludes cumulative production to date of over 65 billion bbl. SOURCE: Riva (1987~. TABLE C-6 U.S. and World Resources of Tar Sandsa (billion bbl) APPENDIX C Measured Resourcesb Speculative In-Place ResourcesC Resources United States 21.6d 4l.ld 62.7d Canada 1700e Venezuela 692f World Total 4000e aA tar sand (or bitumen) deposit is defined as a hydrocarbon deposit having an In situ viscosity greater than 10,000 cp at reservoir conditions or an API gravity less than 10°. In cases where a deposit contains tar (bitumen), heavy oil, and lighter oil, the deposit is considered a tar sand if the majority of the hydrocarbon is not mobile at reservoir conditions (Kuuskraa et al., 1989~. bMeasured resources are defined as that part of the resource that can be deduced to exist from well control, using core analysis and geology. CSpeculative resources are defined as that part of the resource that is presumed to exist from reported tar shows on drillers' logs and other geological interpretation. dKuuskraa et al. (1985~. eInformation supplied by the Alberta Oil Sands and Tar Research Authority of Canada. fConsidine (1977~.
APPENDIX C 143 Texas, California, Kentucky, and several other states. Although the U.S. resource base is not as extensive as in other areas in the world, it is never- theless significant and could support a 20-year oil production of several million barrels per day. Globally, tar sand deposits are distributed throughout the world, but the largest are in the Athabasca region of Western Canada (over 40 percent of an estimated 4 trillion bbl of oil in place) and in the Orinocco Belt of Venezuela. Significant exploitation of this resource currently occurs only in Canada, where it accounts for about 20 percent of total crude oil produc- tion. U.S. and world resources of oil shale are shown in Table C-7. Oil shale is sedimentary rock containing solid organic matter that when heated to around 500°C yields hydrocarbons and other solid products. Although oil shales are found in many places throughout the world, nearly 60 percent of the world's potentially recoverable resources are concentrated in the United States. The second largest resource (about 30 percent of the worldwide recoverable resources) is in Brazil. In the United States the western oil shale deposits account for about 90 percent of the resource base. They are also richer with thicker deposits than the eastern shales, yielding between 20 and 40 U.S. gallons of liquid feedstocks per short ton of raw shale proc- essed. Commercial exploitation of oil shale resources is very limited at the present time (Rive, 1987~. TABLE C-7 U.S. and World Resources of Oil Shale Recoverable Resources (billion barrels of oila) United States Western shales Piceance basin (Colorado) Uinta basin (Utah) Other basins Eastern Shales Kentucky, Indiana, Ohio South America (Brazil) USSR Africa (Zaire) World total 627 380 51 131 65 300 42 38 1007 aRecovery factor = 37.5 percent of estimated in-place resource. SOURCE: Riva (1987~.
144 TABLE C-8 U.S. Natural Gas Resources at Year End 1986 (billion cubic teeth APPENDIX C Existing Technology and Efficiencyb <33.00/Mcf <$5.00/Mcf Advanced Technology and EfficiencyC <$3.00/Mcf <$5.00/Mcf Proved reserves 166 (162) 166 (187) 166 (163) 179 (187) Reserve growths 197 (197) 226 (226) 313(N/A) 483 (N/A) Undiscovered 144 (144) 233 (233) 202 (N/A) 338 (N/A) Low permeability 70 (79) 119 (86) 130 (245) 300 (275) Coalbed methane 8 (13) 12 (26) 40 (51) 90 (65) Shale 10 (17) 15 (20) 30 (37) 40 (46) Total 595 (612) 771 (778) 881 1430 aNumbers in parentheses are from ICE Resources (Kuuskraa et al., 1989~. Note: Mcf = thousand cubic feet. bDOE (1986 dollars). CAAPG (1986 dollars). dIncludes inferred reserves, new pool, and reserve growth from gas and gas-asso- ciated oil reservoirs. SOURCE: Kuuskraa et al. (1989~; AAPG (1989b). TABLE C-9 World Resources of Natural Gas (trillion cubic feet) Proved Reserves Oil & Gas Journal World Oil North America 361.7 357.6 Central and South America 150.1 156.6 Western Europe 218.1 230.5 USSR and Eastern Europe 1479.3 1468.5 Africa 248.7 199.2 Middle East 1084.1 1166.5 Far East and Oceania 255.5 275.3 World total 3797.5 3854.2 SOURCE: ETA (1988~.
APPENDIX C 145 U.S. and world resources of natural gas are shown in Tables C-8 and C-9, respectively. U.S. proved reserves are cu~Ten~cly around 200 Tcf. This accounts for about 5 percent of the world's total, compared to nearly 40 percent for the USSR and 30 percent for the Middle East. U.S. inferred reserves and undiscovered resources are each estimated at over two times proved reserves, and expectations are high that a significant portion of these reserves will in fact be discovered and economically developed (BEG, 1988~. The U.S. endowment of natural gas has been estimated to be in the range of 1500 Tcf (placing it third after the USSR and the Middle East), of which about 45 percent is thought to have been already produced (Rive, 1987~. As noted earlier, recent reviews of the resource base suggest that this endow- ment could in fact be substantially larger. Current annual U.S. consumption of natural gas is around 18 Tcf, of which around 5 percent is imported. World annual consumption is around 65 Tcf (EIA, 1987b, 1989a). U.S. and world resources of coal are shown in Table C-10. The United States has the world's most extensive minable deposits of anthracite and bituminous coal (around 35 percent of the total), followed by the USSR and China. These three countries account for about 60 percent of the recover- able resources in the world (EIA, 1987b). Biomass resources have not been estimated with any certainty, in part because there are as yet no established criteria for defining the economic recoverability of fuels from such resources. TABLE C-10 U.S. and World Resources of Coal (billion short tons) Anthracite and Bituminous Lignite Total Recoverable United States 254.8 36.0 290.8 Other North America 7.0 2.7 9.7 Central arid South America 5.7 5.7 Western Europe 35.5 64.2 99.7 USSR and Eastern Europe 201.5 153.4 354.9 Africa 71.3 71.3 Middle East 0.2 0.2 Far East and Oceania 143.7 42.6 186.3 World total 719.7 298.9 1018.6 SOURCE: EIA (1987b).
