Phase field modeling of hydraulic fracture propagation in spatially variable rock masses

Due to differences in mineral compositions, sedimentary conditions, stress history, and geological processes, the spatial variability of the mechanical properties of rock masses is usually considerable. Therefore, the influence of the spatial variability of rock mass parameters on the irregular propagation of hydraulic fractures should be studied. In this work, an efficient approach is proposed for studying the irregular propagation of hydraulic fractures considering the spatial variability of rock mass parameters; this approach is based on the phase field method and random field theory. Combined with random field theory, the phase field method is adopted to simulate the fracture propagation in a spatially variable rock mass. Random fields of the Young's modulus are generated using the Cholesky decomposition method and then embedded into the phase field model. The influences of different scales of fluctuation of the rock mass parameters' random fields on the fracture shape under fluid-driven conditions are investigated in this study. The results indicate that the spatial variability of the Young's modulus has a significant influence on the propagation of hydraulic fractures.