The Paradox region, within the Colorado Plateau physiographic province, contains such major features as the San Juan, Blanding, Henry Mountain, and Kaiparowits intermontane basins, the San Rafael swell, and the Monument and Circle Cliffs uplifts.

Permian carbonate rocks and sandstone have the greatest potential for future production. The Pennsylvanian section, now the most productive part of the Paleozoic sequence, is second in potential, followed in order of decreasing potential by the Mississippian, Devonian, and Cambrian sections. Ordovician and Silurian rocks are absent in the area.

Permian, Pennsylvanian, Mississippian, and Devonian shelf-carbonate rocks in the area between the Cordilleran geosyncline and the Uncompahgre uplift show much promise for future prolific production from stratigraphic and structural traps. These carbonate rocks probably will be more productive in the western Paradox region than elsewhere in the area. Large accumulations of oil may be found in Mississippian and Devonian carbonate rocks on structures in the Paradox fold and fault belt. Many stratigraphic traps and some structural traps are expected to be present in sequences of very porous and permeable Permian sandstone in southeastern Utah and in northwestern New Mexico.

Mesozoic and Tertiary sequences within the area are predominantly sandstone, siltstone, and shale; they show limited potential for future exploratory success. Cretaceous rocks have been eroded or are near the surface in most localities. Where the Cretaceous is buried in the San Juan basin, it has been drilled extensively to develop the prolific San Juan basin oil and gas fields. Jurassic and Triassic sequences have been explored extensively in the Blanding basin without success. These sequences generally are buried in the San Juan, Henry Mountain, and Kaiparowits basins but may lack associated source rocks. Mesozoic and Tertiary strata are potentially productive in the virtually unexplored Rio Grande trough and San Luis Valley.

Obstacles to finding new production are: (1) the relatively high costs of exploration in large parts of the region; (2) the poor surface accessibility in some areas, which limits the acquisition of sufficient seismic control to map the subsurface structure; (3) the inability to acquire acreage and explore in areas where shallow production already is established; and (4) the prohibition of exploration in national parks and monuments.

Only about 1.8 percent of the total volume of the Paleozoic rocks (43,000 cu mi or 273,000 cu km), excluding the Cambrian System, has been explored. About 413 million bbl of oil and 5.2 trillion cu ft of gas have been produced from sequences of all ages. The amount of oil produced from Paleozoic rocks to date is about 262 million bbl, or 63 percent of the total produced in the Paradox region. The remaining 37 percent is oil produced from Cretaceous rocks in the San Juan basin and on the Uncompahgre Plateau. It is estimated that as much as 30 billion bbl of oil in place remains undiscovered in the Paleozoic section, excluding the Cambrian System.