Analysis of the Hydrogeological Conditions Affecting Fault Response to Nearby Hydraulic Fracturing

Abstract

The response of critically stressed dormant faults to fluid perturbation, by oil and gas production, has been a major public concern because of its link to induced seismicity. In this paper, we study the hydrogeological factors that affect a nearby fault response, during and after hydraulic fracturing (HF) operations, evaluated by the change in Coulomb Failure Stress (CFS) and the rate of seismicity (R) through coupling solid deformation and fluid flow. Our results show that the pore pressure increases rapidly in a fault that is close (hydraulically connected) to HF operations, which might lead to its activation when the injection rate is high. When the fault is adjacent to HF but distant from it, its shallow region is subjected to a stabilizing deformation‐induced normal compressive stress and its deeper region is destabilized under extension. In this case, the fault orientation and damage zone size have a significant effect on the fault's stability and response. On the other hand, decreasing the rate of injection can either increase or decrease the CFS values depending on the fault location and the dominant stresses. Therefore, serious attention should be given to the fault position, its architecture, and the injection rate to help reduce the potential for induced seismicity from HF. Our findings are verified and confirmed using the case of the Duvernay formation in Alberta, Canada, where the reported seismic data correlate with high CFS and R values.

Impacts of Rate of Change in Effective Stress and Inertial Effects on Fault Slip Behavior: New Insights Into Injection‐Induced Earthquakes

“…In addition to a majority of natural earthquakes, the remaining seismic events are related to anthropogenic activities (Yehya, et al., 2022), viz, water injection induced earthquakes (Alghannam & Juanes, 2020; Healy et al., 1968). The injection of large volumes of fluids into the Earth's subsurface has the potential to elevate fluid pressures and reactivate faults (Cappa et al., 2009; Keranen et al., 2014; Luccio et al., 2018; Zoback & Gorelick, 2012).…”