Thomas F. Newkirk, 1971. "Possible Future Petroleum Potential of Jurassic, Western Gulf Basin", Future Petroleum Provinces of the United States—Their Geology and Potential, Volumes 1 & 2, Ira H. Cram
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Reservoir beds of porous sandstones and carbonate rocks are widespread in the Jurassic province of the Gulf Coast. They have been found in structural and stratigraphic situations which have resulted in the production of nearly 613 million bbl of oil and condensate and 3.9 trillion cu ft of gas. Virtually all of the production is confined to the mature areas in Arkansas and Louisiana and to the semideveloped areas in Texas and Mississippi, and is principally from the Schuler, Haynesville, and Smackover Formations.
If long-range growth is to be realized in the maturely developed provinces, which are in the stage of declining producing rates, or in the semideveloped areas, which are being exploited rapidly, the exploration search must turn to unconventional traps and other Jurassic strata. The remaining immature areas, many of which are in the greater depth range, have had varied degrees of investigation. Trends which now are undergoing rapid development in semideveloped areas may be extended into adjacent immature areas. In other immature regions, although favorable structural and stratigraphic conditions may be expected, present data suggest that greater areal selectivity must be exercised and that there will be comparatively more areas of poor reservoir quality. Jurassic formations at depths greater than 20,000 ft (6,100 m) are not expected to be of widespread productive significance.
The principal problems to be solved in the search for future reserves are of a technological and an economic nature; the technological aspects are largely in the field of exploration, and the economic problems are in both exploration and production.
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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.