The Oriskany in West Virginia

Abstract

Commercial oil and gas possibilities from the Oriskany series of the Devonian in West Virginia were first demonstrated in 1918, but no commercial production was developed until 1930. In 1934-35 three fields, now having a proved area of 43,000 acres, were opened in Kanawha County. The Oriskany sandstone is a sheet deposit in West Virginia and underlies approximately three-fourths of the state from its outcrop along the eastern edge before it thins and disappears in the western part. The sand ranges in thickness from probably more than 200 feet in the northern part to an average of 40 feet in the producing fields. A very definite water table is present on the eastern margin of the gas belt. This is apparently trapped water, as rock pressures in the Kanawha County fields do not indicate hydrostatic control. The sand varies from coarse-grained (1. +millimeter) to fine-grained (0.1 millimeter) sand. Normally, the upper part of the sand is much coarser than the middle or lower section; however, alternate coarse- and fine-bedded sand is very common and is very sugges ive of cross-bedding. Calcium carbonate is the main cementing material in the sand, although near the western limits of deposition silica is the predominating cementing medium. Porosity in the proved fields ranges from 6.8 to 11 per cent. Open flows in the various fields range from 46,000 to 22 million cubic feet, with rock pressures varying from 1,100 to 1,940 pounds. Carbon dioxide and distillate are present in the gas in these fields. The carbon-dioxide content of the gas increases in wells high on the structure, while the distillate decreases. To date, 21 dry holes and 124 gas wells have been completed, and a daily open flow of 625,725,158 cubic feet developed. Anticlinal structure is of primary importance for production, but proper sand conditions are also necessary. Due to converge ce, anticlines, as expressed on the deeper horizons, are shifted from their surface or shallow subsurface location. The reflection seismograph has been a very valuable aid in checking the positions of these axes and will, no doubt, help materially in areas where water is thought to be present.