Lower Pennsylvanian sediments in the Fort Worth basin are prolific hydrocarbon producers. These sediments are deltaic in nature and are characterized by complex stratigraphy. The problem of locating new reserves and exploiting producing zones depends largely on subsurface mapping and a detailed knowledge of the stratigraphy.

The Atokan and Strawn progradational sediments in the study area consist of 13 separate depositional cycles, each of which isolated several reservoirs. Each of these groups of reservoirs has potential for structural and/or stratigraphic hydrocarbon traps. Mapping located prospects in the Strawn on noses in the Dog Bend Limestone, in Atokan conglomerates in structural lows associated with faulting in the Marble Falls, and in deeper horizons, such as Mississippian reefs and Ellenburger highs, and on structural highs in the Marble Falls.

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