ABSTRACT: Combined Geological and Surface Geochemical Methods Discover Agaritta and Brady Creek Fields, Concho County, Texas

SAUNDERS, DONALD F., and K. R. BURSON, Recon Exploration, Inc., Dallas, TX, J. J. BROWN, Indigo Oil, Inc., Dallas, TX, and C. K. THOMPSON, Recon Exploration, Inc., Dallas, TX

From December 1987 to March 1991, 25 prospects in the lower King Sandstone (Upper Pennsylvanian Cisco) play in Concho County, Texas, were tested by several operators. They used combinations of subsurface geology, reconnaissance airborne gas sensing, surface radiometrics, soil magnetic susceptibility, and soil gas hydrocarbon measurements to define prospects. Six new King Sandstone field discoveries or extensions and three deeper pay Goen Limestone field discoveries resulted in a 36% exploratory success rate. The total exploration and development cost was approximately $0.67 per bbl of proven producing oil reserves.

As examples, we present the discovery of Brady Creek and Agaritta fields. Agaritta field is one of the two largest of the new field discoveries with estimated proven producing recoverable reserves of 6,000,000 BO. Its discovery was based on a combination of (1) airborne hydrocarbon sensing, (2) interstitial soil gas hydrocarbon data, (3) soil magnetic susceptibility measurements, and (4) surface potassium and uranium concentrations measured by gamma-ray spectrometry.

Interstitial soil gas hydrocarbon anomalies combined with soil magnetic susceptibility anomalies provided the best detailed surface guidance to Agaritta field. These were supported locally by radiometric anomalies.

The Brady Creek field is interpreted to be a possible crevasse splay deposit. The Agaritta field is interpreted to be a point bar deposit. Both fields are stratigraphic traps.

AAPG Search and Discovery Article #91018©1992 AAPG Southwest Section Meeting, Midland, Texas, April 21-24, 1992 (2009)