Abstract

Dewey and Custer Counties lie in the approximate geographic center of the Ana-darko basin of western Oklahoma. Geologically, they are situated on the northern shelf area of the basin. No production of oil or gas existed in these counties prior to 1957. By the summer of 1964, in a period of seven years, over 200 wells had been drilled, which established one trillion cubic feet of gas and 30 million barrels of oil. The investment in these wells is approximately 30 million dollars and the value of the production is approximately 240 million dollars. The return on the investment should be 8:1. The accumulation of hydrocarbons is due to a variety of traps at various depths. The Putnam pool is a reef bank limestone accumulation of gas and oil in the Oswego Limestone of Pennsylvanian age and occurs at 9,700 feet. This pool contains 50 gas-condensate wells and 80 oil wells, accounting for 500 billion CFG and 30 million barrels of oil. The pool is three miles wide and approximately 30 miles long.

The Lenora pool produces from a stratigraphic trap in the Morrow sand of Lower Pennsylvanian age at a depth of 10,500 feet. Twenty wells on 640-acre spacing account for approximately 40 billion CFG. Custer City is a deep gas pool producing from the Hunton Limestone at 14,000 feet. Five wells have been drilled. Large open flow potentials, some exceeding 150 million CFGPD, characterize some of the wells. Individual reserves in this pool, in some wells, exceed 50 billion CFG.

Five new pipelines market gas in the area; whereas, seven years ago, no lines were present.

Future development in these two counties should see reserves doubled. New pools in the Morrow, Tonkawa, Cherokee, and Hunton are expected. The area is only 20 per cent evaluated.