Geologic Case History of Slocum Dome, Anderson County, Texas

Abstract

The Slocum dome is a deep-seated interior salt-dome in northeast Texas. It furnishes a recent example of a prospect rediscovered. Dense well control and reliable stratigraphic correlation allow a subsurface geologic case history that tells a story continuously repeated in the older oil-producing provinces. Oil production was established in the Slocum area in 1935 from Woodbine and sub-Clarksville sands of Upper Cretaceous age. The initial production was located on the northwest flank of the dome and was depleted by 1938. Significant production from the same formations on the southeast flank was discovered in 1956 and active development has resulted in 15 new reservoirs. Ninety per cent of the cumulative production of nearly 2 million barrels through 1957 is credited to the new reservoirs. The dome is characterized by an elliptical outline and a central graben located transverse to the elongate axis. Radial faulting and stratigraphic variation combine to form several different types of oil and gas traps on the flanks of the dome. Cross sections and isopachous maps reveal sand truncation during structural growth and the changing effect of domal growth on the area of its influence. The geologic history of this dome has economic applications in northeast Texas and in areas of similar geology. Evidence furnished concerning the area condemned by a single dry hole probably applies in every oil province.