Advanced Numerical Simulation of Fault Slip and Induced Seismicity- An Innovative Approach

To assess the risks related to induced seismicity due to operations in the subsurface, it is essential to employ appropriate simulation tools to assess the seismicity responses of faults. This paper presents a numerical workflow developed as part of the DynSEIS innovation project, which employs slip-weakening behavior through an advanced numerical framework. Initially, the approach was applied to 2D models, and the results were benchmarked against literature. A 3D realistic model was subsequently developed based on data from a real gas field and 3D numerical simulations were calibrated against field data and the seismogenic responses of the faults were assessed. Through these efforts, the use of an explicit solver in dynamic mode for calculating surface accelerations and velocities was demonstrated. Fault weakening laws with various descriptions for the fault (discrete, planes of weakness) were employed in different cases giving very consistent results compared to literature work. The capacity to quantify the surface response in terms of expected velocities and accelerations has been confirmed. The developed methodology demonstrates that using slip-weakening laws within relevant numerical schemes allows for better assessment of seismogenic fault slip, fault slip propagation, and the magnitude of energy released which is beneficial for better derisking of induced seismicity due to subsurface operations.