Pennsylvanian sediments deposited between the Sierra Grande--Frontrangia positive elements and the Central Kansas uplift-Nemaha ridge trend contain large amounts of hydrocarbons. In the Anadarko basin alone almost 2 billion bbl of oil, more than 20 trillion cu ft of gas, and up to 700 million bbl of gas liquids eventually will be recovered from Pennsylvanian reservoirs. Mocane--Laverne, Camrick, Hansford, Greenwood, Keyes, and Elk City are six major Pennsylvanian fields in the western Anadarko basin. They have up to 2 billion equivalent bbls of recoverable oil in traps ranging from anticlines to purely stratigraphic. The reservoirs range from carbonate banks to alluvial sandstone and are of Morrowan to Virgilian ages.

The Anadarko and Denver basins always have been considered to be separate geologic provinces. However, during Pennsylvanian time they were part of the same geological regimen and properly should be considered together. The Amarillo-Wichita Mountains, Sierra Grande uplift and Frontrangia comprise a tectonic rim with a common orogenic history during the Pennsylvanian. The distribution of facies and depositional environments from this rim toward the stable-shelf area is similar and closely related across a broad area covering eastern Colorado, western Kansas, western Oklahoma, and parts of Nebraska, Wyoming, and Texas.

Only the Anadarko basin part of this large area has been explored actively and most of eastern Colorado and western Kansas remains a relatively virgin area for Paleozoic exploration. Because the relations of facies and environments in the whole area are similar, because the basin structure and geologic history are closely related, and because the Anadarko basin has been the scene of prolific discoveries, it could follow that the Pennsylvanian potential of the relatively unexplored area of western Kansas and eastern Colorado is very good.

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