Petrophysical facies mapping of the Pennsylvanian Cline Shale, Midland Basin, West Texas.


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The Cline Shale is a Pennsylvanian unconventional shale resource play located in the Midland Basin, west Texas. This study evaluates the depositional, stratigraphic and petrologic controls on Cline Shale reservoir quality and their spatial distribution as determined from core-calibrated petrophysical facies across the study area. Nine depositional facies were observed and described from the cored Gunn36 #1 well located in Howard County. Five petrophysical facies were derived from the statistical comparison of core observed depositional facies with corresponding digital well log data. Two additional petrophysical facies that are not calibrated to core observations account for both the distribution of undifferentiated shallow-marine carbonates across the Horseshoe Atoll and borehole washouts. By mapping the petrophysical facies, it was determined that the distribution of the most prospective Organic Rich Shale (ORS) facies, located principally in southwest Howard and northeast Glasscock counties, was controlled by proximity to the contemporaneous Horseshoe Atoll and Eastern Shelf.



Cline Shale. Midland Basin. Horseshoe Atoll. Eastern Shelf. Pennsylvanian. Shale. Reservoir. Unconventional.