Petrophysical lithofacies modeling of the upper Pennsylvanian Cline Shale in the Midland Basin, West Texas.


The Cline Shale is an upper Pennsylvanian interval of interstratified organic-rich shale, inorganic shale, and allochthonous carbonate beds, and is currently an active unconventional exploration target within the Midland Basin of west Texas. This study compares core-observed depositional facies to petrophysical well logs within the Gunn36 #1 well (API# 4222737197) of Howard County, Texas in order to identify predictors of organic richness and carbonate content for use in Cline Shale mapping. A depositional facies model was constructed through analysis of 365 feet (111 m) of continuous core through the Cline Shale. Eight petrophysical parameters were evaluated for their ability to predict both depositional facies and organic richness. A transform utilizing gamma ray and density porosity logs was created that differentiates organic-rich and inorganic shale and predicts the distribution of allochthonous carbonate and dolomitized intervals.



Cline Shale. Pennsylvanian.