A novel three-dimensional hydraulic fracturing model based on continuum-discontinuum element method

摘要

Based on continuum-discontinuum element method (CDEM), a three-dimensional hydraulic fracturing model which can consider simultaneously the continuum field, crack opening, pore seepage field and fracture seepage field is proposed in this paper. In this model, the CDEM method is used to calculate the continuum field and crack opening, and the finite volume method (FVM) is adopted to calculate the seepage field, in which the pore seepage is characterized by Darcy's law and the fracture seepage is expressed by the cubic law. Through the comparison and analysis with four analytical solutions and one experimental phenomenon, the fracture pattern is predicted accurately and the poroelastic stress is captured as well. In addition, the result of a disk with one injection hole suggests that this model can not only depict the fluid pressure distribution in fractures and pores of rock matrix, but also trace the initiation, propagation and intersection of cracks driven by fluid. (C) 2021 Elsevier B.V. All rights reserved.