Induced earthquakes caused by destabilized faults due to the production and injection of underground fluids pose an inevitable anthropogenic* hazard. In addition to damage to surface structures, the longer term danger is the integrity of the subsurface and the resulting leakage of harmful fluids.
During production of fluids from the subsurface, the formation pressure decreases; conversely, during injection the pressure increases. Both scenarios can have an effect on fault instability that is associated to seismic events—and possibly damaging earthquakes. To assess and mitigate such risks, it is critical to improve the understanding of the underlying geomechanical processes. To undertake such challenges, a multidisciplinary approach is applied.
3D Finite Element Model
From the 3D structural geological model of the subsurface, a 3D finite element model is derived. The 3D finite element model is populated with geomechanical properties and pressures, such as from 1D geomechanical models for the wells in the field. From modeled pressure and temperature changes, the stresses are computed via a finite element simulation using Abaqus.
The fault stability is assessed using the computed stresses. The Monte Carlo method is applied to the fault slip stability calculations to quantify the reliability of the prediction. Finally, the validity of the models is confirmed by comparing the results of the simulation with historic records of observed earthquakes.
To facilitate this advanced workflow, Baker Hughes (a leading oilfield service provider and an Abaqus Integration Partner) has integrated Abaqus with their JewelSuite subsurface and geomechanical modeling software. This unique combination provides a single environment for geomodeling and mechanical simulation that simplifies and accelerates the coupled geomechanical analysis.
