A coupled multi-physics modeling framework for induced seismicity

Abstract:

There is compelling evidence that moderate-magnitude seismicity in the central and eastern US is on the rise. Many of these earthquakes are attributable to anthropogenic injection of fluids into deep formations resulting in incidents where state regulators have even intervened. Earthquakes occur when a high-pressure fluid (water or CO₂) enters a fault, reducing its resistance to shear failure and causing runaway sliding. However, induced seismicity does not manifest as a solitary event, but rather as a sequence of earthquakes evolving in time and space. Additionally, one needs to consider the changes in the permeability due to slip within a fault and the subsequent effects on fluid transport and pressure build-up. A modeling framework that addresses the complex two-way coupling between seismicity and fluid-flow is thus needed. In this work, a new parallel physics-based coupled framework for induced seismicity that couples the slip in faults and fluid flow is presented. The framework couples the highly parallel subsurface flow code PFLOTRAN (www.pflotran.org) and a fast Fourier transform based earthquake simulator QK3. Stresses in the fault are evaluated using Biot’s formulation in PFLOTRAN and is used to calculate slip in QK3. Permeability is updated based on the slip in the fault which in turn influences flow. Application of the framework to synthetic examples and datasets from Colorado and Oklahoma will also be discussed.