Reservoir characterization of the Frontier Formation, Powell field, Powder River Basin WY

Abstract

The Upper Cretaceous Wall Creek Member of the Frontier Formation is a prolific oil and gas producer in the Powder River Basin of north east Wyoming. It has been a focus for drillers in recent years as horizontal drilling and hydraulic fracturing help exploit the hydrocarbon resource of the tight sandstone reservoir. Millions of barrels of oil have been produced from this oil prone formation since the late 19th century. The Upper Cretaceous, Turonian Wall Creek Member of the Frontier Formation represents the distal reaches of a progradational clastic wedge that formed in response to the Sevier Orogeny. Sediments were shed from the Sevier Highlands into the Western Interior Basin (WIB). The Wall Creek Member of the Frontier Formation produces at Powell Field in the center of the Powder River Basin near the deep basin axis. Vertical well production originates from reworked, medium to coarse grained sandstones. This research integrates data and interpretations to characterize the Wall Creek Member of the Frontier Formation at Powell Field. Petrophysical evaluation, well production, X-Ray diffraction, core analysis, and petrographic analysis were used to characterize the Wall Creek Member of the Frontier Formation. The Simandoux shaly sand petrophysical model matches core derived water saturation values best and was used to produce subsurface maps that highlight areas for further unconventional well development. Eight total core facies are identified as part of the core analysis that suggest a shallow marine, wave and tidal influenced delta front environment. Petrographic observations of the main reservoir facies indicate primary porosity is preserved from early chlorite coating of quartz grains prior to calcite cementation and quartz overgrowths forming.