A fully coupled three-dimensional hydro-mechanical finite discrete element approach with real porous seepage for simulating 3D hydraulic fracturing

A fully coupled 3D hydro-mechanical model with real porous seepage is presented for simulating hydraulic fracturing. In this model, fluid flow in a fracture is expressed by 2D fracture seepage in the broken joint elements based on the Cubic law, while fluid flow in the rock matrix is represented by 3D porous seepage in the tetrahedral elements based on Darcy's law. Several problems that have closed-form solutions and a 3D fracturing problem are given to verify the model. The simulation results show that the model can capture crack initiation and propagation, and the fluid pressure evolution during hydraulic fracturing.