Geomechanical Investigation of Hydraulic Fracturing-Induced Fault Slippage and Seismicity in Naturally Fractured Duvernay Unconventional Play

ABSTRACT: This study presents an integrated investigation of the causes of recorded earthquakes in Alberta, Canada. The workflow includes identifying fault presence through 3D seismic processing and interpretation, building a 3D geological model with seismic interpretation results and well data, 1D geomechanical models, a 3D geomechanical model and a discrete fracture network model, followed by hydraulic fracturing simulation and fluid flow simulation to identify lateral fluid movement pathways from the injection wells to the fault. With the pressure changes from the fluid flow simulations, one-way coupled geomechanical simulations reveal the fault shear slip reactivation as a result of pressure increase due to hydraulic fracturing and lateral fluid migration through the fracture network. The predicted dextral strike-slip displacement along the fault matches the location, time and mechanism of the recorded earthquakes. The approach explains not only why the earthquakes occurred, but also how they occurred. It can be used as a new way of understanding the mechanisms of earthquakes induced by hydraulic fracturing.