Natural fractures dominate the permeability of tight gas reservoirs in the Mesaverde Formation of the Piceance Creek Basin, northwestern Colorado. Roughly 450 natural fractures have been detected in reservoir sandstones and siltstones in 4200 ft of core from the U.S. Department of Energy's Multiwell Experiment (MWX). Sixty percent of the fractures are calcite-mineralized, vertical extension fractures that are probably the greatest contributors to reservoir permeability. However, the contribution of the other mineralized fractures should not be discounted.

You can access this article if you purchase or spend a download.