North Cowden field, Ector County, Texas

Geographically, the North Cowden field is on the transition between the Llano Estacado at the north and the Edwards Plateau at the south. Geologically, it is on the eastern margin of the Central Basin platform. The presence of a structure was indicated by subsurface data, and the discovery well was completed by the Southern Crude Oil Purchasing Company in September, 1930. The producing structure is an anticline 712 miles long, with about 100 feet of closure indicated by present control. Oil is obtained from sands and limestone of lower Whitehorse age, and production is most prolific on the east, or basinward, flank of the structure-a condition due, at least in part, to the thickening of sands basinward from the crest. The first "pay" is reached at an average depth of 4,027 feet, and the average amount of pay section penetrated is 89 feet. A gas cap exists in the first pay zone on the higher parts of the structure. Progressive folding during Whitehorse and Salado time moved the axis of the structure basinward. Post-Rustler movement shifted it about 114 miles west to its present position. The present productive area of the field includes 9,760 acres. The Cowden anhydrite is defined in this paper.