Petrographic Differentiation of Fluvial and Estuarine Sands, Fall River Formation, Powder River Basin, Wyoming: ABSTRACT

Abstract

The authors examined 170 core and cuttings samples of the Fall River Sandstone from 28 wells in three areas of the Powder River basin: Buck Draw, Silver Spoon, and East Flank. Information from thin sections on sorting, textures, grain size, detrital mineralogies, clay types, and early diagenesis were used to differentiate depositional facies and evaluate controls on porosity. Most of the porosity in the Fall River Sandstone is secondary, and its development is a function of depositional facies and geographic location.