Modeling hydraulic fracture in heterogeneous rock materials using permeability-based hydraulic fracture model

Abstract

Hydraulic fracturing is one of the most important techniques for enhancing oil/gas production. The permeability-based hydraulic fracture (PHF) model, which is based on the smeared-crack method and considers the interaction between the pore pressure and solid phase, is adopted in the present study for a fully-coupled simulation of the hydraulic fracture in a heterogeneous rock formation. The level set method (LSM), which is used to describe the distribution of material properties of heterogeneous rocks, is coupled with the PHF model. Using the coupled PHF–LSM model, a series of finite element method (FEM) simulations are carried out to investigate the characteristics of a hydraulic fracture (e.g., the breakdown pressure and fracture propagation) in heterogeneous rocks. Three types of heterogeneous rocks are examined: layered rock, rock with distributed inclusions, and rock with random spatial variations in the material properties. The results of the numerical simulations show that the coupled PHF–LSM model can describe the material interface without changing the FEM mesh used to discretize the physical domain. Further, the model effectively simulates hydraulic-fracturing problems for various heterogeneous rocks.