Abstract

The Elsinore; Pikes Peak, East; GMW; and Sierra Madera fields are located in south-central Pecos County, Texas, approximately twenty-five miles southwest of Fort Stockton.

The Elsinore field was discovered by the Hunt Oil Company’s No. 52 Elsinore Royalty Company, drilled in 1957-58. The discovery well of the Pikes Peak, East field was the Texas Pacific Oil Company, Inc. No. 1 Elsinore Cattle Company, drilled in 1972. The GMW field was discovered in 1975 by the BTA Oil Company’s No. 1 J.V.S. Allison “7405”. The Sierra Madera field was discovered by the L.R. French No. 1 Sierra Madera, completed in 1977.

The producing formations in these fields include the Devonian, Silurian, Fusselman, and Montoya. There is minor production from the Wolfcamp.

The structure of the Pikes Peak, East field is an asymmetrical anticline with its axis oriented in a northwest-southeast direction with the steep flank of the fold on the eastern side. The gas-water contact is indicated to be between -9200 and -9250 ft. The highest base of the Woodford datum is found in the Hunt No. 52 Elsinore at -7506 ft and the lowest is found in the Continental Oil Company’s No. 2 J.V. Allison at -9066 ft.

To date there have been 28 completions in the Elsinore field; five in the Pikes Peak, East field; four in the GMW field; and one in the Sierra Madera field. This makes a total of 38 gas wells. As of 1-1-77, the Elsinore field had produced 54.8 billion cubic feet of gas and the Pikes Peak, East field had produced 14.8 billion cubic feet of gas. 1976 production for the Elsinore field was 32.3 billion cubic feet of gas and the Pikes Peak, East field production was 4.15 billion cubic feet of gas.

Initial potentials range from a low of 660,000 cubic feet of gas per day to a high of 4.3 billion cubic feet of gas per day from the Texas Pacific Oil Company’s No. 6 Montgomery-Fulk (largest well-potential in the U.S.A.). Estimated ultimate recovery for the fields ranges from 160 to 320 billion cubic feet of gas. Estimated recoverable reserves on a per-well basis for 640 acres range from 5 to 10 billion cubic feet of gas. Gas analyses show 44 to 45.13 percent carbon dioxide.

Wells take 90 days to drill and complete and cost approximately 1.5 million dollars.