3D geomechanical modelling of induced seismicity including intersecting faults and reservoir compartments

Abstract

To investigate the physical processes behind induced seismicities due to, for example, production of hydrocarbons from a reservoir, most of the earlier studies performed geomechanical simulations on a simple reservoir geometry. The effect of fluid depletion is, in general, simulated for such a simple geometry. Neglecting the contribution of realistic 3-D reservoir geometries can lead to a wrong estimation of the incremental stress field. A reliable estimate of the induced stress field is key to producing meaningful simulation results. We perform geomechanical simulations on a simple fault model as well as a more realistic model based on the known geological structures at the earthquake source-region in Zeerijp region, the Netherlands. Our results demonstrate that the angle of the fault intersection affects the incremental stress field, including the effective normal stress, the shear stress, and hence, the Coulomb stress and the SCU value. Our results also show a shift in the rupture pattern and the location of the maximum slip on the fault plane. We conclude that, to properly evaluate the effects of production activities and to simulate precisely the in-situ stress field and the induced seismicity, the incorporation of a realistic reservoir structure in modelling is essential.