Reservoir stimulation in naturally fractured reservoirs is significantly impacted by the presence of fractures. This paper presents an improved 3D numerical model for fluid flow, heat transfer and injection induced microseismicity in a network of fractures. A stochastic fracture network model accounting for fracture spatial distribution and detailed individual fracture properties such as aperture, size and orientation is generated. The connectivity of the fracture network is then identified using a searching algorithm. Fluid is assumed to flow within the interconnected set of fractures. Pressure distribution within the interconnected network is solved from a set of mass balance equations written at each fracture center. The flow pattern on individual fracture planes is then obtained analytically. To model heat transfer, energy conservation is written for each fracture as a balance between convected energy, energy dissipated by conduction and the change of energy retained by the volume of fluid within the fractures. Fracture propagation and shear slippage are simulated integrally to account for their combined effects on fracture network response. Fracture shear slippage is assumed to be governed by the Mohr-Coulomb failure criterion and the corresponding microseismic events are identified. This model is applied to simulate the response of a large scale fracture network to fluid injection. Simulation results show that during injection, the increase in pressure inside fully connected fractures could lead to slip events and cause some fractures to propagate. The hydraulic conductivity of the fracture network is improved through fracture shear dilation and fracture propagation.

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