The Numerical Simulation and Characterization of Complex Fracture Network Propagation in Multistage Fracturing with Fractal Theory

Abstract

To investigate complex fracturing and the influencing factors of simultaneous fracture propagation in horizontal wells, a three-cluster fracture propagation model that is controlled by fracture surface displacement parameters is established. When performing multistage fracturing on reservoirs with a relatively high development degree of natural fractures, staged multicluster fracturing in horizontal wells is one of the commonly used technical methods for volume fracturing. Two frequently encountered problems are multifracture extension and interfracture stress interference between fractures. The characteristics of the coal mechanics parameters of coalbed methane (CBM) blocks in northwestern China are analyzed by probability statistics to obtain the elastic modulus and Poisson’s ratio. With the interactive development environment of the MATLAB-PYTHON-FEM platform, a numerical model of fracture network expansion under the staged fracturing of horizontal wells is constructed. The stress interference level between fractures and the fractal expansion mechanism of fracture networks are analyzed under different influencing factors, including the fractal dimensions of natural joints, fracturing fluid pumping rate, and inhomogeneity coefficient of the in situ stress.