3D geomechanical modeling of induced seismic slips considering realistic reservoir geometry with intersecting faults

Geomechanical simulations of induced seismicity generally involve a simple reservoir geometry in terms of reservoir structure and fault distribution. Because the depletion of the reservoir controls the incremental stress field, the geometry of the reservoir has a substantial influence on the occurrence of induced earthquakes. We develop geomechanical models based on a realistic geological model of the reservoir in the Groningen gas field. The model captures the main characteristics of the reservoir structures in the Zeerijp region. Through quasi-static and dynamic simulations, we observe that a smaller intersection angle between the two normal faults in the Zeerijp region causes an increase in the incremental Coulomb stress at the lower reservoir juxtaposition adjacent to the intersection. As a result, this intersection angle strongly affects the location of the initial seismic slip, the rupture pattern, and the location of the maximum slip. Our simulation produces an earthquake of magnitude MW 3.0, due to fault reactivation occurring at a reservoir depletion value of 26 MPa. These values are similar to those for the Zeerijp 2018 earthquake of ML 3.4. The location of the simulated rupture is close to the inverted hypocenter location for the 2018 earthquake. Our results suggest that it is crucial to incorporate realistic reservoir structures when simulating induced seismicity in a specific region.