| dc.description.abstract | Marmaton Group (Desmoinesian) Granite Wash deposits of the Elk City Field, in eastern Beckham and western Washita counties, Oklahoma, are composed of sandstones, conglomerates, and mudstones that were deposited as fan deltas with changing proximity to the Amarillo-Wichita uplift. Sandstones, conglomerates and shales can be divided into five zones (Marmaton A-B, C, D, E, F) separated by flooding surfaces. These zones can be further divided into transgressive and highstand system tracts. Structurally, the Elk City Field is composed of a northwest trending anticline bounded by at least two faults on its flanks. Thin section analysis and XRD results suggest that the mineralogy of the sediment source is responsible for the variable well-log responses. An artificial-neural network combined with proper well-log cut-off values and porosity-lithology relations are used to estimate lithologies in non-cored wells by utilizing cores and well logs. The stratigraphic framework, estimated lithology logs, porosity logs, and the spatial statistics from variography are used to construct 3-D lithology and porosity models that illustrate lateral and stratigraphic variability in reservoir quality. Different lithology models show the relation between the sequence stratigraphy and reservoir distribution as well as the effect of using a neural network and porosity-lithology relation in lithology estimation and the resulting reservoir properties. Marmaton C interval has the highest connectivity both for conglomerates (88.1%) and sandstones (67.1%). Marmaton A-B interval has the greatest pore volume. Highstand system tracts have greater amount of reservoir, reservoir connectivity and reservoir pore volume than transgressive system tracts. | en_US |
