Rupture Behavior of Hydraulic Fracture Induced-triggered Seismicity

Through the use of a unique hybrid seismic recording network, we investigate the rupture characteristics of induced-triggered events with M>0 associated with a hydraulic fracture stimulation in an unconventional reservoir. This unique approach incorporates high-frequency recordings utilizing downhole 3C 15 Hz omni-directional geophones situated near the reservoir and thereby the rupture initiation, intermediate-depth downhole 3C Force Balance Accelerometers (0.1Hz) and geophones (4.5Hz), and near-surface, low-frequency 3C recordings obtained using Force Balance Accelerometers (0.1Hz) and geophones (1 Hz, 2Hz and 4.5Hz) that allowed for investigation of overall rupture characteristics within the frequency bandwidth of effectively 0.1Hz to over 500Hz. For these larger events, the recordings allowed for an in-depth investigation of the dynamics of the sub-fracture failures during the rupture process and growth of the overall fracture from initiation to arrest. Our initial results suggests that overall shearing is the dominant mode of failure, whereas the rupture characteristics of the sub-fracture failures are more complex than a simple shearing process and include strong tensile components of failure. Our measurements of rupture complexity, seismic efficiency, rupture velocity and estimates of stress release further support the idea that the sub-fractures are characterized by failures of multiple asperities that exhibit self-similar behavior within themselves.