3D simulation of fluid-pressure-induced fracture nucleation and growth in rock samples

Fluid-pressure-driven (or hydraulic) fracturing of rocks is used in several applications including stimulation of unconventional reservoirs, permeability enhancement of geothermal systems, and rock mass pre-conditioning in deep mining. In recent years, there has been a fast growing interest in the development and use of advanced numerical methods to better describe hydraulic fracturing processes. In this paper, recent advances in hydraulic fracturing modeling using a three-dimensional hybrid finite-discrete element (FDEM) code are presented. FDEM is an explicit numerical method which combines continuum mechanics principles with discrete element algorithms to simulate multiple interacting deformable fracturable solids. The effectiveness of the approach is illustrated by simulating two cases of fracture nucleation and growth around a pressurized cylindrical cavity in a homogeneous and isotropic medium. Realistic emergent pressure response and fracture patterns are obtained with the simulated fracture networks highlighting a distinctive 3D interaction of individual fractures around the location of injection.