A full 3D hydraulic fracturing simulator based on the finite element method and its analytical and physical verifications

ABSTRACT: The finite element method is an important tool to simulate hydraulic fracturing as it can take into account of rock heterogeneities and interactions of hydraulic fractures in a natural manner without compromise. In this work, we developed a full 3D hydraulic fracturing simulator using the finite element method. The simulator solves two coupled sets of equations simultaneously that govern fluid flow and leak-off in fractures, and rock matrix deformation and fracture propagation, respectively. We validated the simulator by comparing its simulations with semi-analytical solutions and experimental data in published literatures. Six cases were run for complete verification with analytical solutions that cover all energy dissipation regimes together with all fluid storage ones. We simulated a KGD model and an axis-symmetric one for the verification with physical experiments. The numerical simulations have excellent agreements with analytical solutions and with physical experiments. Stability and sensitivity of the FEM simulator to mesh size are discussed. The finite element simulator can be used for the design of hydraulic fracturing treatments.