ABSTRACT

The Cherokita and Wakita Trends produce oil and gas from sandstone reservoirs of the middle Cherokee Red Fork sandstone. The two closely spaced trends are roughly parallel to each other, extend about 50 mi east-west across northern Grant and Alfalfa Counties in north-central Oklahoma, and then continue another 15-20 mi southwest into the Anadarko Basin in southern Woods and Major Counties.

The Cherokita and Wakita Trends were developed largely during the late 1950s and 1960s. The Cherokita Trend has produced ~23.7 MMBO (million barrels of oil) and 149 BCFG (billion cubic feet of gas), and the Wakita Trend to the north has produced ~10.2 MMBO and 152 BCFG.

Much speculation has existed about the depositional origin of sandstone in these Trends. Some geologists interpreted the elongate sandstone trends to be shoreline deposits formed along the northern edge of the "Enid Embayment" of Swanson (1967) and Withrow (1968) as a result of eustatic sea-level changes during the time of Red Fork sandstone deposition. In contrast, the current investigation, as well as the opinion of most geologists, holds that the trends are erosional (incised) valleys that formed in response to lowering of eustatic sea level (falling stage). The predominant sandstone facies is fluvial-probably longitudinal bars, although estuarine deposits are also believed present. This conclusion is based on the evaluation of many well logs, regional mapping, literature review, core examinations, and personal correspondence.

The vast majority of well logs penetrating the Red Fork sandstone in the Cherokita and Wakita Trends show sandstone with a sharp basal contact with shale-and blocky to fining-upward textural profile typical of fluvial deposits. Basal scour has eroded below the underlying Inola Limestone marker bed in many places, and the distal extent of both trends terminate to the southwest in marine delta-front deposits characterized by a coarsening-upward textural profile as best seen on gamma-ray and resistivity logs. This latter facies is generally much thicker than the terrestrial channel deposits because accommodation space farther basinward is greater.

The implication of making a correct interpretation of the depositional origin of these sandstones is important in determining the logical extension of these and other similar trends. As in other parts of Oklahoma, the Red Fork has a tendency to form long, incised-channel complexes that terminate in a low-stand delta. The Wakita and Cherokita Trends are no exceptions, and, regionally, they too pass basinward into delta-front sequences that are exceptional producers of natural gas.