Numerical Investigation of Hydraulic Stimulation in Pohang Fractured Geothermal Reservoir, South Korea

Abstract

In this study, we investigate numerically the hydro-mechanical behavior of fractured crystalline rock due to hydraulic stimulation at the Pohang Enhanced Geothermal site in South Korea. Several hydraulic stimulations were performed in wells PX-1 and PX-2. We use the commercial code FracMan (Golder Associates) that enables studying dynamic hydro-mechanical coupled processes in fractured media in three dimensions combining the finite element method with a discrete fracture network. The software is used to simulate fluid pressure perturbation and related stress redistribution at fractures during hydraulic stimulation. Our numerical simulation shows that pressure history match can be obtained by partitioning the treatment into separate phases. The simulated extent of the 0.01 MPa overpressure contour at the end of the treatment equals to ~180 m around the injection point.