Woodford Shale Gas Production Versus Fault Intensity — A Quantitative Analysis
Christopher M. Robinson
St. Mary Land and Exploration, Tulsa, OK 74136, [email protected]
Horizontal drilling and massive hydraulic fracturing have made the Woodford formation in the western Arkoma Basin of Oklahoma an attractive target for natural gas production. However, values of estimated ultimate recovery (EUR) of natural gas vary significantly across the play. Individual well performance depends on numerous geologic, drilling and completion factors. One of the more important geologic factors in central Coal County, Oklahoma, is proximity to seismically-identifiable faults. Detailed structure maps made from 3D seismic data and associated cross-plots show quantitatively that as near-well fault intensity increases, the EUR/frac of the well decreases. A fault’s vertical separation does not seem to be a first-order influence on how much that particular fault reduces the productivity of the well. This implies that so long as a fault is large enough to be seismically-identifiable, it acts as a leak-off pathway which reduces the overall effectiveness of the fracture stimulation. These results suggest that operators should adjust their completion style as the seismically-identifiable fault intensity increases.
AAPG Search and Discovery Article #90095©2009 AAPG Eastern Section Meeting, Evansville, Indiana, September 20-22, 2009