The National Petroleum Council's Region 6 Subcommittee study group concludes that substantial areas and volumes of potential source and reservoir rock remain unexplored in the western Gulf basin. A minimum volume of 454,000 cu mi (1,891,800 cu km) of sedimentary rock with favorable hydrocarbon potential, either gas or oil, is present in the study area. The Potential Gas Committee estimates that 406 trillion cu ft of gas will be found in the future in Region 6. Of this total, 275 trillion cu ft is classified as "possible" and "speculative." Recoverable crude oil reserves added in the future from this same area will be approximately 15 billion bbl. This figure does not include extensions or upward revisions of recoverable crude oil from discoveries made before January 1, 1969.
Excellent potential exists in the unexplored and partially explored strata of the Pleistocene and upper Mio- cene-Pliocene in the offshore area, in the Upper Cretaceous Tuscaloosa in the southeastern part of Region 6, in Lower Cretaceous (Trinity) sandstone and carbonate rocks, in extensions of partially explored "post-Louann Salt" formations of Jurassic age, and in lower Paleozoic rocks in the Black Warrior basin.
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The geology of the entire United States, including the continental shelf and slope, was studied by petroleum geologists to determine its petroleum potential. Prospective areas of the 11 regions were assessed qualitatively and, usually, quantitatively.
The prospective basinal area covers approximately 3.2 million sq mi (statute; 8.3 million sq km) and contains approximately 6 million cu mi (25 million cu km) of sedimentary rock above basement or 30,000 ft (9,144 m). Other less prospective areas are, in the aggregate, large.
The prospective area has not been explored adequately. Many high-potential areas are indicated by the geology and extent of exploration, particularly in parts of Alaska, California, Colorado, Louisiana, Mississippi, Montana, New Mexico, North Dakota, Oklahoma, Texas, Utah, and Wyoming, and in parts of the offshore of Alaska, California, Louisiana, and Texas. The prospective Atlantic, Florida, and Alaska continental shelves, and the entire continental slope, barely have been touched by drilling, and other prospective areas and depths on land and the continental shelf remain largely unexplored.
Estimates of potential crude oil reserves of the basinal area only, exclusive of known reserves, range from 227 to 436 billion bbl of original oil in place. The potential probably exceeds the mean of 332 billion bbl. Approximately 32 percent of the oil in place would be recoverable at known rates of recovery. Ultimately, the rate of recovery may reach 60 percent.
Estimates of potential natural gas reserves exclusive of known reserves range from 595 to 1,227 trillion cu ft of recoverable natural gas. The gas potential also probably exceeds the mean of 911 trillion cu ft.
The ultimate petroleum potential of the United States, including known reserves, may exceed 432 billion bbl of crude oil, 1,543 trillion cu ft of natural gas, and 49 billion bbl of natural gas liquids.
Finding and developing the large petroleum potential will require a great amount of drilling because a significant percentage of the visualized undiscovered crude oil and natural gas is in stratigraphic traps, combination stratigraphic and structural traps, reefs, and complex structural situations. Estimates of future domestic demand call for accelerated exploration. To the extent that policies of industry and government militate against accelerated exploration, particularly drilling, a high percentage of the petroleum resources of the United States will not be reduced to possession.