Possible Future Petroleum Provinces of Eocene and Paleocene, Western Gulf Basin
C. L. Lofton, W. M. Adams, 1971. "Possible Future Petroleum Provinces of Eocene and Paleocene, Western Gulf Basin", Future Petroleum Provinces of the United States—Their Geology and Potential, Volumes 1 & 2, Ira H. Cram
Download citation file:
This investigation revealed two important future petroleum provinces—gas in Texas and oil in Louisiana—related to the Wilcox Group. A possible future oil province, covering parts of Texas and Louisiana, is predicted also for the Claiborne Group. No new province is foreseen for the Jackson Group. The new provinces predicted for the Wilcox and Claiborne Groups more appropriately might be described as coastward extensions of existing trends. Possible petroleum provinces associated with Eocene-Paleocene sedimentary rocks to 30,00(Mt (9,144 m) depth in the western Gulf basin are considered on the assumption that technological advances will permit drilling and producing of wells to such depth.
No significant production in the western Gulf basin has been associated with Paleocene rocks; the Paleocene section consists mainly of shale and other nonreservoir rock. Considerable quantities of both oil and gas have been found in the established Eocene trends. Currently, there are 501 gas, 1,048 oil, and 377 oil and gas fields which have produced from the Eocene. Cumulative production to January 1, 1969, totaled more than 4.2 trillion cu ft of gas and 2.8 billion bbl of oil. These figures, and all similar figures quoted in this report, are exclusive of casinghead gas, natural gas liquids, and gas flared in past years.
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.