The Region 10 study covered a large part of the Appalachian basin—west approximately to the axis of the Cincinnati arch, east to the boundary of the Fall Line with the Atlantic coastal plain, north to the U.S.- Canada border, including all of New England, and south to include eastern Tennessee and western North Carolina.
The major tectonic features of the area are shown in Figure 1. Discussion of Region 10 is on a state or contiguous-state (such as New England) basis. Arbitrary geologic divisions of the basin area could have been established as a basis for discussion, but the basin geology from northeast to southwest involves mainly gradual change rather than distinct geologic boundaries. This basin, in fact, is unusual for its relative tectonic uniformity from northeast to southwest. Stratigraphic changes also are relatively gradual in this direction. More distinct geologic divisions are evident from northwest to southeast. However, since approximately half of the geologists engaged in the Region 10 study were state geologic personnel having particular expertise in their own states, and most of the favorable petroleum area is in the rather uniform Appalachian Plateau province, the decision was made to treat the region on a state basis. Appendix I shows each senior author's report area in Region 10 and gives the names of all authors.
Although the Atlantic offshore area of New England is included in Region 11, Page suggests that there is a close geologic relation between the New England onshore and offshore areas and therefore includes Atlantic offshore potential in his discussion of the New England part of Region 10.
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.