Investigation of hydraulic fracture branching in porous media with a hybrid finite element and peridynamic approach

Abstract

Simulation of complex fracture patterns in porous media can help understand and improve hydraulic fracturing processes, with potential for significant impact on enhancing oil and gas recovery. In this paper, a fully coupled hydraulic fracture propagation simulation method employing a hybrid finite element method (FEM) and peridynamic (PD) approach is presented. Considering the ability of PD in solving discontinuous problems, the area where cracks can potentially occur is discretised by PD and the crack-free area is discretised by FEM. The solid deformation and fracture propagation are captured by PD and FEM, while the fluid flow in both the reservoir and fracture is simulated with FEM. The whole process is solved in a monolithic way with an implicit scheme. The presented method demonstrates the capability of modelling complex dynamic crack propagation via benchmark examples. Branching phenomenon is then investigated with the proposed model. It is found that faster loading rate, lower-energy release rate, and more brittle and impermeable media will cause crack branching more easily.