An integral equation algorithm for 3-D simulation of pore pressure in a porous elastic medium with heterogeneities

SUMMARY We present an algorithm for simulation of pore pressure due to a 3-D surface water reservoir, on a porous elastic half-space with heterogeneity of different permeability/hydraulic diffusivity. The perturbation in pore pressure due to the anomalous permeability of the heterogeneity is calculated by introducing a secondary source term in the porous elastic diffusion equation. The resulting equation is solved using integral equation method. Green's functions of porous elastic half-space are used in this algorithm. As an illustrative example, the case of Koyna–Warna region, a well-known site of reservoir triggered seismicity in India, is simulated. Pore pressure due to reservoir loading is calculated in the fault zones and the surrounding medium. This algorithm will have a wide application as it can be applied to various cases, such as fluid injection, increased stream discharge, porous elastic relaxation, etc., where the diffusion of pore pressure in the porous elastic medium with heterogeneities is significant.