We present an approach to studying resolvability and limitations of detecting rock failure mechanisms during fracture growth or activation form passive seismic monitoring data. This approach includes numerical geomechanic modeling of incremental rock failure including associated generation and propagation of elastic waves. Then we record these waves in the far field (several wavelengths away from the source) and invert P- and S-wave amplitudes for seismic moment tensor. Thus we can derive an effective point source which gives the approximation of the amplitudes. These results establish connection between geomechanic models of rock failure (hydraulic fracture growth, fracture activation during production) and a passive seismic monitoring data. microseismic monitoring. Thus we can see which scenarios of fracture growth or activization can be resolved from passive seismic monitoring data. In particular, we show examples indicating that the radiation pattern of waves generated by fracture growth can be reasonably described by a point source defined by the moment tensor. On the other hand the moment-tensor inversion may lead to an incorrect interpretation of the hydraulic fracture growth direction depending on regional confining stress field.
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