Geomechanical Assessment of Seismic Potential from Hydraulic Fracturing

The impact of hydraulic fracturing on a Horn River Basin fault was examined to quantify seismic potential or hazard. A geomechancial model was designed to investigate the mechanism of fault activation and the impact of fracturing at different locations around the fault. The model is used to simulate hydraulic fracture growth through a discrete fracture network, examining the pore pressure diffusion and associated fracture dilation and shearing. Based on the geomechanical deformation, the seismic activity can be predicted and used to compare with the actual seismicity monitored during the fracture treatment. The microseismic geomechanics study indicated that the stimulated fracture network had to grow directly into the fault in order for the injection pressure front to trigger fault slip. Geomechanical assessment of absolute seismic potential can be used to modify the engineering design prior to operations to minimize the seismic hazard including the placement of the well, and modifiy staging along the well to avoid fracturing in the regions likely to lead to fault activation. In scenarios where induced seismicity occurs during the treatment, the method can also be used to examine operational changes to lessen the relative seismic hazard.