Future Oil and Gas Potential of Northeast Arizona
John R. Barwin, Robert W. King, Charles A. Hassenfratz, 1971. "Future Oil and Gas Potential of Northeast Arizona", Future Petroleum Provinces of the United States—Their Geology and Potential, Volumes 1 & 2, Ira H. Cram
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Northeastern Arizona, comprising Apache, Navajo, and Coconino Counties, has moderate to poor overall potential for future oil and gas reserves. Strati- graphic traps and a few undrilled anticlinal features will be important in future discoveries. Drilling depths are generally less than 8,000 ft (2,438 m). Leasing, accessibility, and markets may be problems in certain areas.
The Paradox basin of northern Apache County has the best oil potential in northeastern Arizona. Carbonate banks or reefs in the Pennsylvanian Hermosa Formation are particularly prospective. Oil accumulations in Mississippian and Devonian rocks are likely to be found in subtle stratigraphic traps because most of the obvious anticlines have been drilled. Traps completely filled with inert gas are detrimental to oil occurrence. Fields similar to Dineh-bi-Keyah, which produces from a Tertiary sill, may be difficult to find. The Permian in the southwestern Paradox basin offers only slight oil potential, and the Triassic and Jurassic rocks are not considered prospective. Leases can be obtained by competitive bid from the Navajo Indians.
The Black Mesa basin, centering in northern Navajo County, has been sparsely drilled and offers only moderate future oil potential. Past drilling has been disappointing, but a few oil shows and thin porosity zones have been found in the Devonian and Mississip- pian. The Pennsylvanian and Lower Permian are largely a redbed sequence with little potential. The Coconino Sandstone of Permian age is devoid of oil shows, producing only helium-bearing inert gas at Pinta Dome on the south. Undrilled anticlinal trends are present in the northern Black Mesa basin, and there are pre- Pennsylvanian truncation possibilities in the eastern and southern parts of the basin.
The small Holbrook basin, which centers in southern Navajo County, has some future oil potential. Wells have found porosity and a few shows in Permian, Pennsylvanian, Mississippian, and Devonian rocks.
The general Flagstaff area of southern Coconino County may have oil potential in Mississippian and Devonian rocks. Oil shows are present along the Mogollon Rim outcrop and in several wells.
The Preston Bench—Kaibito Saddle area of northeastern Coconino and northern Navajo Counties could have potential in the pre-Pennsylvanian, but good prospects will be difficult to find. The crests of the Defiance and Kaibab uplifts are not considered prospective.
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.