Cottonwood Creek-Hewitt Trend Arbuckle Play (Southern Oklahoma): Example of Complexly Faulted and Fractured Karst Trap: ABSTRACT

Abstract

The Hewitt field (T4, 5S, R1, 2W), located along the northwest-southeast-trending Wichita-Criner Hills anticlinorium, is the ninth largest field in Oklahoma with ultimate recovery projected to exceed 250 million bbl. The development of the anticlinorium was initiated by the Wichita orogeny during the Morrowan, forming north-south-trending folds. During the Atokan, extensive erosional forces removed thick sequences and exposed the Ordovician Arbuckle Group. The uplift was subsequently covered by Deese and Hoxbar clastic sediments during the Middle Pennsylvanian. The Late Pennsylvanian Arbuckle orogeny produced compressional stress from the southwest and resulted in refolding of the uplift features and movement along high-angle faults. The recent discovery of prolific hydrocarbon reserves in Ordovician carbonates (Canadian, Arbuckle Group) has renewed interest along this prolific trend. The productive reservoir in the Hewitt-Cottonwood Creek area is the dolomitic Brown zone (Kindblade Formation), located approximately 1000 ft below the top of the Arbuckle group. The zone consists of crystalline dolomite, 500-600 ft thick, with adequate porosity and permeability developed to form significant reservoirs due to karstification of the extensive fracture systems. The Bray zone (West Spring Creek Formation-upper Arbuckle Group) has production in the Healdton and southwestern Lone Grove fields from fractured, arenaceous, finely granular dolomite and more » may be an additional possible reservoir. The combination of good untested reservoirs located on structural features associated with block faulting, as illustrated by seismic sections across the Criner fault, gives an excellent indication that the trend may have great future potential within a mature province. « less