The Effect of Varying Fluid Injection Activities on Induced Earthquakes through Joint-Enriched Finite Element Analyses

Subsurface fluid injection into sedimentary reservoirs is potentially responsible for the sharply rising number of seismic events in oil and gas production regions. To assess the effects of fluid injection activities on fault reactivation and slip, we construct a hydro-mechanical joint-enriched finite element model, comprised of a multi-layer sequence embedded with a favorably-oriented normal fault. We consider six injection scenarios to address the effects of anthropogenic parameters including injection rate and injection volume on the stability of seismogenic fault. Simulation results demonstrate that maximum excess pore pressure and stress perturbation are highly dependent on the injection strategy. The injection program with faster initial rate may induce early fault reactivation. Higher injection volume also could result in a higher potential of fault reactivation and slip. The incorporation of joint elements into the model allows the capture of progressive fault damage under hydro-mechanical couplings. This study highlights the importance of appropriately-designed injection well operations in minimizing the likelihood of induced seismic events.