Martin W. Schramm, JR., William M. Caplan, 1971. "Southeastern Oklahoma and Northern Arkansas", Future Petroleum Provinces of the United States—Their Geology and Potential, Volumes 1 & 2, Ira H. Cram
Download citation file:
Southeastern Oklahoma and northern Arkansas (Fig. 41) include an area of approximately 21.0 sq mi (54,390 sq km); the thickness of sedimentary rock ranges from 3,000 to 30.0 ft (914 to 9,144 m). Of the area considered, 9,000 sq mi (23,310 sq km) is in the Arkoma basin, 7,000 sq mi (18,130 sq km) is in the Boston Mountains of the southernmost Ozark region, and 5,000 sq mi (12,950 sq km) is in the frontal belt of the Ouachita Mountains. The average thickness of strata is roughly 2.6 mi (4.2 km) and the gross volume of rock is about 55,000 cu mi (229,180 cu km), of which 50,000 cu mi (208,350 cu km) is at depths of less than 20,000 ft (6,096 m; Tulsa Geol. Soc., 1951). Most of this rock fills the Arkoma basin.
The region is essentially a nonassociated dry gas province. Several giant gas fields now produce from Lower Pennsylvanian sandstone beds in the Arkoma basin. The future potential of the area lies in (1) continued exploration and development of stratigraphic traps in Lower Pennsylvanian sandstone, which should provide significant "probable" gas reserves, and (2) exploration of the relatively unexplored, deeper Lower Devonian—Silurian and Ordovician strata, in which the geology is radically different from that of the younger rocks, and in which substantial “possible” or “speculative” reserves should be found.
Figures & Tables
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.