THE UPPER CRETACEOUS TURNER SANDSTONE AS AN EMERGING OIL AND GAS PLAY, EASTERN POWDER RIVER BASIN, WYOMING

The Upper Cretaceous Turner Sandstone produces throughout much of the eastern Powder River Basin of Wyoming. Often interpreted as a nearshore, marine bar sequence, the Turner Sandstone is a series of interbedded and bioturbated very fine-grained sands and shales with a basal medium-grained sandstone. The entire sequence is typically between 150 and 175 ft in the eastern Powder River Basin consisting of several sand benches becoming less sandy to the east. The basal sand is most often the completion target and often has the best developed porosity and permeability. Recently horizontal drilling and completion methods have made the low resistivity/low contrast pay zones of the Turner Sandstone a more enticing target by increasing contact with the formation.

The Turner Sandstone is the middle member of the Carlile Shale in the eastern Powder River Basin. It disconformably overlies the Pool Creek Member and is conformably overlain by the Sage Breaks Member. The Turner Member of the Carlile Shale is equivalent to the upper Frontier Formation of the western Powder River Basin based on ammonites present in outcrop. The Turner Sandstone was originally described from outcrops near the town of Newcastle, Wyoming along the eastern margin of the Powder River Basin. The Turner Sandstone is an emerging play that warrants further study. This presentation provides an overview of the petrophysical log characteristics, cores, and production for each currently productive area in the Powder River Basin.