Hydromechanical coupled cohesive zone modeling of induced earthquakes under fluid injections

In this work, we configure a fully coupled hydro-mechanical finite element model to study the interaction between fault zone and injected fluids. This generic model simulates fluid injection into a porous reservoir near a preferentially oriented normal fault that extends from the sedimentary layer into the basement. We use cohesive zone elements to characterize the damage initiation and propagation associated with the reactivation and slip of fault and incorporates the degradation of friction angle into the slip process. Comparative analyses are carried out to reveal the influences of the distance between injection well and fault on fault reactivation. Through this model, we observe the coupled effect of injection rate and injection distance on the onset of fault reactivation and the ensuing fault slip. High volume injection at a close field site may exert a more significant perturbation on the stress state of the fault. Our study highlights the importance of injection site selection and injection activity plan in minimizing the likelihood of induced seismic events.