Correlation and Facies Analysis in Exploration for Subtle Traps Within Hunton Group, Oklahoma

Richard D. Fritz

The bulk of Hunton production to date is associated with rather well-defined structural and/or truncation-style traps. Yet the trapping mechanism in these settings, to a large extent, depends on the development of particular depositional facies within the Hunton Group.

Accurate correlation and subdivision of the Hunton require an understanding of the overall depositional environment and history. The depositional model for the Silurian Chimneyhill and Henryhouse formations and the Devonian Haragan and Bois d'Arc formations is a carbonate ramp. Both aggradational and progradational sequences formed, as did several unconformities during periods of erosion and nondeposition. The Frisco, however, was deposited on submerged paleohighs, probably as a mud-mound deposit.

Using the foregoing depositional models as a guide, subdivisions of the Hunton, based on regional markers related to changes in sea level between progradational episodes, can be recognized and correlated throughout the Anadarko-Arkoma region. Comparing core data and log signatures, along with applying depositional cycles, permits more detailed correlations as their component facies are recognized by log character. Reservoir-prone facies within the carbonate cycles can then be identified, correlated, and mapped.

The Cheyenne Valley field in Major County, Oklahoma, represents an excellent example of the relationship between facies and reservoir development that can be delineated by correlation from an environmental perspective. This field is an exploration model for subtle traps in the carbonates of the Hunton Group.

AAPG Search and Discovery Article #91039©1987 AAPG Mid-Continent Section Meeting, Tulsa, Oklahoma, September 27-29, 1987.