Enhanced Geothermal System (EGS) is most concerned about flow paths, induced seismicity, fracture dilation and propagation. EGS development requires an ability to accurately predict the flow paths, temperatures over time. This work first presents a framework for quantitatively predicting the behavior of fracture network, induced seismicity and flow paths in a rock mass. A fully coupled thermo-hydro-mechanical-seismic (THMS) finite element model with 3D discrete fracture network is described that is able to incorporate processes of fracture flow, rock deformation, shear dilation, fracture propagation and induced seismicity. A semi-deterministic fracture network is generated by combining the data from image logs, core with properties of fractures (e.g., length and asperity) which follow a stochastic distribution. Fracture propagation in shear/wing crack manner under injection is taken into account. This coupled method allows for multiple seismic events to occur on and around a fracture. As an application, the coupled method is applied to a COLLAB stimulation (May 24, stim-II @164 notch) to predict the flow path and induced seismicity. The model has been able to simulate the injection profile, induced seismicity and fracture propagation with good agreement with field observations.

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