Regional computer-aided stratigraphic studies in a 185-sq mi (481 sq km) area resulted in the broad definition and ultimate drilling of the Mixon Creek prospect and the discovery of Valentine field, Lavaca County. About 50 wells were picked for structural tops, interval sand counts, and isopach data. Simple computer printouts were contoured and analyzed to determine the trends of successive delta-front or barrier-island alignments. Ultimately a drill site was chosen updip from a show on a seismic nose.

Development of the field resulted from drilling essentially offset locations in a northeast-southwest alignment along what was believed to be a lower Wilcox barrier island cut by a tidal channel at the southwest end and truncation by a shale-filled gorge on the northeast. The Menking field discovery was made in a stratigraphically separate lower Wilcox sand in an attempt to extend the Valentine field southwest. Additional drilling along the northwest margins of these fields shows that the stratigraphic relations are complicated and difficult to solve with subsurface data. Two Valentine wells were cored, slabbed, and analyzed petrographically. R. R. Berg of Texas A&M University has suggested that these data indicate a deep marine-turbidite environment.

Valentine field has 12 wells and covers approximately 1,000 acres (400 ha.). The productive Technick sand averages 12 ft (3.6 m) in thickness with porosity of 19 to 21% and permeability of 10 to 30 md. Recoverable reserves are estimated at 1.2 million bbl. Through 1978, 758,801 bbl of oil and 2,575 Mcf of gas have been produced.

There are four wells in the Menking field draining about 300 acres (120 ha.). The principal production comes from the Kubena sand which averages 18.9% porosity and 23.9 md permeability. Recoveries are low because of restricted reservoir communication. Reserves are estimated at 300,000 bbl and production through

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1978 is 113,309 bbl of oil and a small amount of gas.

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