We conducted an integrated geomechanics case study of the Woodford shale to understand the effectiveness of multi-stage hydraulic fracturing. The study involves two parallel horizontal wells, each about 5,000 feet long with ~15 frac stages. Analysis of Instantaneous Shut-In Pressure (ISIP) of each frac stage indicates significant variations of the minimum horizontal principal stress (Shmin) magnitude along the well length. We observed that Shmin by stage rises with the content of clay and organic matter. The number of micro-earthquakes and the amount of proppant embedment, seems to be affected by the Shmin variation. By combining the analysis of the compositional log and the well steering data, we found that the wellbore traveled in and out of the target zone and penetrated different facies of the Woodford shale along its path, resulting variations of lithology and consequently patchy stimulation performance. The distribution of microseismic events away from the well both vertically and laterally is also influenced by the lithology variation, as well as the presence of pad-sized faults.

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