Depositional Environments of Pennsylvanian Red Fork Sandstone in Northeastern Anadarko Basin, Oklahoma

Abstract

The Pennsylvanian Red Fork Sandstone produces oil and gas in a large area of north-central Oklahoma. There are indications that several oil fields comparable with the Burbank field (0.5 billion bbl) can be found in northwestern Oklahoma during the next few years by use of available well control for detailed reconstruction of the depositional environments of the Red Fork Sandstone. The Red Fork Sandstone was deposited west of the Nemaha ridge during the time of Cherokee deposition (Desmoinesian) in the large Enid embayment. There were four fairly distinct phases of sand deposition; an early phase during which channel sand was deposited, two phases of offshore-bar deposition, and a brief period when seas receded from the area and channel sand was deposited. On the basis of this interpretation, several unusual problems can be explained. The Oakdale field in southeastern Woods County has oil reserves of nearly 30 million bbl in the Red Fork Sandstone. The sandstone in this field is in two separate linear bands which include sandstone deposited during the first three phases. The Southwest Wakita field in Grant County produces from two fairly distinct Red Fork Sandstone bodies that were deposited during phase 2. The Wakita trend (phase 3) in Grant County produces from a thin Red Fork Sandstone slightly higher stratigraphically than those at Oakdale and Southwest Wakita. In the Cheyenne Valley field in Major County, the Red Fork is interpreted to be a channel sandstone deposited during phase 4, and it is higher stratigraphically than sandstone in the previously mentioned fields. This channel-type deposit is productive, i fairly widespread in the Enid embayment, and has several distinguishing characteristics. By reconstruction of the depositional environments of the Red Fork Sandstone and by interpretation of this unit as representing four fairly distinct phases, the Red Fork is shown to be a reservoir with great potential in the Anadarko basin. There are several good indications of undiscovered major productive areas. They can be found by an exploration program based on detailed reconstruction of depositional environments to explain the problems and to make possible the interpretations necessary to find prospective Red Fork Sandstone trends.