Stratigraphy and Reservoir Characteristics of the Desmoinesian Granite Wash, Southern Anadarko Basin

Abstract

The Desmoinesian Granite Wash is a hydrocarbon-bearing interval within the Anadarko Basin of Oklahoma and Texas that was deposited as a series of alluvial fans, fan deltas, and deepwater deposits and is composed of clastic and carbonate sediments derived primarily from the Amarillo-Wichita Uplift. The Desmoinesian Granite Wash, located in Beckham County, Oklahoma and Wheeler County, Texas, includes a series of vertically stacked conglomerates and tight-gas sandstones and shales that exhibit a complex stratigraphic architecture, highly variable lithofacies, and correspondingly heterogeneous reservoir properties. The stratigraphic and reservoir characteristics of the Desmoinesian Granite Wash (Texas and Oklahoma) are established based on cores, thin sections, well logs, and XRF measurements. The Desmoinesian series deposits in the southern Anadarko Basin include interbedded sandstones and conglomerates that transition to layered and amalgamated sheet sandstones which thin laterally into mudstones to the north (basinward). There are at least four regional, correlatable flooding surfaces in the Desmoinesian that are also thought to be self-sourcing in this liquids-rich interval. Having reached thermal maturity roughly 250 Ma, the TOC content of shales throughout the interval ranges from 0–18% and contain a mixture of kerogen types (II and III). In Oklahoma, the Desmoinesian series is greatly over-pressured making drilling difficult. Porosity in this interval varies from 2–18% with low permeability values; generally < 0.1 mD. The Desmoinesian Granite Wash exhibits numerous and frequent lithofacies changes. XRF analyses of cuttings and cored intervals show how elemental concentrations vary laterally and stratigraphically with lithology, lithofacies, and clay concentrations. Calculated lithology and porosity logs are used as constraints in 3-D reservoir models to illustrate the controls that stratigraphic architecture and lithofacies play on petrophysical properties and related reservoir productivity.

AAPG Datapages/Search and Discovery Article #90216 ©2015 AAPG Annual Convention and Exhibition, Denver, CO., May 31 - June 3, 2015