Modelling fault reactivation with characteristic stress-drop terms

Abstract

Abstract. Predicting shear failure that leads to the reactivation of faults during the injection of fluids in the subsurface is difficult since it inherently involves an enormous complexity of flow processes interacting with geomechanics. However, understanding and predicting induced seismicity is of great importance. Various approaches to modelling shear failure have been suggested recently. They are all dependent on the prediction of the pressure and stress field, which requires the solution of partial differential equations for flow and for geomechanics. Given a pressure and corresponding mechanical responses, shear slip can be detected using a failure criterion. We propose using characteristic values for stress drops occurring in a failure event as sinks in the geomechanical equation. This approach is discussed in this article and illustrated with an example.

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“…During fault reactivation, fluid pressures may be considerably perturbed within and immediately adjacent to the fault. However, such perturbations are typically very short-lived [69] and are therefore not included in the model.…”

“…Energies 2021, 14, x FOR PEER REVIEW 14 of 30 pressures may be considerably perturbed within and immediately adjacent to the fault. However, such perturbations are typically very short-lived [69] and are therefore not included in the model. Figure 4 shows the porosity distribution within the symmetry cell that comprises the numerical model used for the analyses.…”