Study on Mesostructure Boundary Modeling and Hydraulic Fracture Propagation for Rock Material Based on the PHF-LSM-MT Method

Natural heterogeneous rock material has complex mesostructure and distribution characteristics. An approach to model inclusions with irregular boundary by using the Perlin noise, and considering features, e. g., specific radius, semi-axial ratio, orientation angle and plane filling rate, is introduced. In order to include the mesostructure characteristics of rock material at integration point, the permeability-based hydraulic fracture level set method (PHF-LSM) is improved by introducing the Mori-Tanaka (MT) homogenization method based on a coupled fluid-solid elastoplastic theory. The proposed PHF-LSM-MT method is verified by error analysis. Finally, the propagation features of equivalent fracture zone in heterogeneous rock material were simulated by using the proposed method. The results indicate that the water pressure at injection point first increases and rapidly decreases, and the breakdown pressure decreases while the inclusion fraction increases.