Petroleum Potential of Modoc Plateau and Cascade Range, Northeastern California
Thomas E. Gay, JR., Robert Streitz, 1971. "Petroleum Potential of Modoc Plateau and Cascade Range, Northeastern California", Future Petroleum Provinces of the United States—Their Geology and Potential, Volumes 1 & 2, Ira H. Cram
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The potential for future discovery of oil in the Modoc Plateau and Cascade Range area of northeastern California is dim. If marine strata are present anywhere in the area (except the minor Cretaceous rocks at the west edge), they are buried at undetermined depths beneath Tertiary and Quaternary pyro- clastic and flow rocks and freshwater-lake beds. Neither surface geology, gravity surveys, nor the few scattered drillholes appear to encourage hope for oil production, or even for the presence of oil-bearing strata, in the area.
Cretaceous marine sandstones of the Chico and Horn- brook Formations extend at least a few miles beneath the volcanic cover at the west edge of the Modoc- Cascade area, but have proved to be barren of oil and gas to date. Although marine Cretaceous rocks are exposed in central Oregon, none were found by drilling as deep as 12,000 ft (3,658 m) in volcanic rocks a few miles north of the northeastern boundary of this area.
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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.