THE RATIONALE FOR ASSESSMENT OF UNDISCOVERED, ECONOMICALLY RECOVERABLE OIL AND GAS IN CENTRAL AND NORTHERN ARIZONA: PLAY ANALYSES OF SEVEN FAVORABLE AREAS

摘要: Seven oil and gas plays, totalling about 12,750 square miles, have been identified in the northern Arizona assessment province of U.S. Geological Survey. This is roughly north 34°15' N. lat. its western half 33°15' eastern half. These seven plays good potential for future discovery economic accumulations reservoirs middle late Paleozoic age. Assessments are based on favorable attributes source reservoir rocks plus geothermal maturity, trap development, migration timing. Arizona's only petroleum production occurs northeast corner Apache County where first field was discovered 1954. Currently, flammable extracted from Pennsylvanian with minor Mississippian Devonian rocks. Six outlined Colorado Plateau physiographic one Cordilleran overthrust belt Basin Range extreme northwestern Arizona. Plays are: 1) Devonian, Mississippian, structures; 2) through Permian primarily structural traps Hurricane Fault Uinkaret area Arizona; 3) both stratigraphic greater Black Mesa basin northeastern 4) bioherm carbonate mound along southern margin Paradox 5) northern, western, flanks Defiance uplift 6) Holbrook anticline region southwestern east-central and, 7) anticlines updip pinchouts within 1 All speculative except for: part which has very production, (Blanding subprovince) fields, flank contains largest producing field, Dineh-bi-Keyah. The latter a 20-million-barrel (ultimate recovery) 1967. It produces fractured igneous sill Oligocene age section. Regional anisotropy basement rock paleotopography strongly influenced growth younger tectonic features depositional patterns expressed northwest-northeast geophysical trends. Continued analyses these trends may provide keys to finding more Northern frontier exploration inviting targets potential. There approximately 800 boreholes province; almost were drilled gas. remainder exploring geothermal, helium, mineral resources, as tests. About 130, or 35 percent, between 5,000 8,500 feet deep none being deeper than feet. Excluding development wells existing oil, gas, helium drilling geographically uneven an overall average density borehole per 140 miles. In many instances too shallow reach best reservoirs, strategies not always modern principles. Very few tested sedimentary section beneath volcanic cover. Over 26,000 miles (40 percent) study Indian reservation lands; unfavorable leasing policies sometimes discouraged areas (Peirce, 1982).