Stratigraphic Architecture and Reservoir Characteristics of the Desmoinesian Granite Wash (Marmaton Group), Elk City Field, Anadarko Basin, Oklahoma

Abstract

The Marmaton Group of the Pennsylvanian Granite Wash in the western Oklahoma and the Texas Panhandle is an active producing interval for oil and gas from arkosic sandstones and conglomerates that were eroded from the Amarillo-Wichita uplift and deposited into the adjacent Anadarko Basin as alluvial fan, fan delta, and deep water deposits. Marmaton Group (Desmoinesian) Granite Wash deposits in Elk City Field, in eastern Beckham and western Washita counties, Oklahoma, are composed of arkosic sandstones, conglomerates, and mudstones that have a complex stratigraphic architecture, variable lithofacies, and heterogeneous reservoir properties. The stratigraphy, structure, and reservoir characteristics of the Marmaton Group are established through the integration of core, well logs, core-to-log calibration, and 3-D reservoir modeling methods. The dominant lithofacies are orthoconglomerate, paraconglomerate, granule-pebble-bearing sandstone, slumped sandstone, massive sandstone, parallel-stratified sandstone, cross-stratified sandstone, bioturbated sandstone, bioturbated mudstone, and bioturbated to fossiliferous mudstone. Well logs indicate that the different sandstone and conglomerate lithologies form intervals that are separated by at least four distinct and laterally extensive shales which are believed to be capped by regional flooding surfaces and are useful for correlation. Artificial-neural-network (ANN) techniques are used to estimate lithologies in non-cored wells by utilizing core and well logs; primarily gamma ray, neutron porosity, density porosity, and resistivity. The stratigraphic framework, estimated lithology logs, other logs, and spatial statistics from variography are used to construct 3-D lithology and petrophysical property models. The models illustrate the structural and stratigraphic variability in reservoir quality and are used to interpret the geological controls on reservoir-quality distribution.

AAPG Datapages/Search and Discovery Article #90259 ©2016 AAPG Annual Convention and Exhibition, Calgary, Alberta, Canada, June 19-22, 2016