UC Riverside

Hydraulic fracturing (HF) is a widely employed technique for stimulating low-permeable underground reservoirs to enhance hydrocarbon production. Current HF models for the design of industrial HF treatments commonly assume fractures grow in an isotropic elastic solid. However, most sedimentary rocks, such as shales and mudstones, are made of fine-scale layers that should be treated as transversely isotropic (TI) solids. The impact of such anisotropy on HF treatments has not been fully addressed in current HF models for practical applications. In this thesis, we focus on the study of vertical planar three-dimensional hydraulic fractures (PL3D) propagating perpendicular to the isotropic planes of various TI solids. The PL3D model is constructed based on the displacement discontinuity method (DDM) for fractures and the finite volume method (FVM) for fluid flow within fractures. The formula of the stress field of a dislocation segment in a general anisotropic elastic solid is incorporated into DDM. As a consequence, we find the horizontal extension of fracture is greater than the vertical extension in TI solids. This elongation is more obvious for a solid with stronger anisotropy. The fracture energy is another important factor that can also have a significant impact on fracture geometry. These effects, influenced by various elastic parameters, are delineated and presented in quantitative detail. Finally, we demonstrate that approximate methods may be used to address the transversely isotropic effects in isotropic models for computational efficiency.