The behavior of natural fractures at the hydraulic fracturing (HF) treatment is one of the most important considerations in increasing the production from this kind of reservoirs. Therefore, considering the interaction between the natural fractures and hydraulic fractures can have great impact on the analysis and design of fracturing process. Due to the existence of such natural fractures, the perturbation stress regime around the tip of hydraulic fracture leads to some deviation in the propagation of path of hydraulic fracture. Increasing the ratio of transverse stress to the interaction stress results in a reduction in the deviation of hydraulic fracturing propagation trajectory in the vicinity of natural fracture. In this study, we modeled a hydraulic fracture with the extended finite element method (XFEM) using a cohesive-zone technique. The XFEM is used to discrete the equations, allowing for the simulation of induced fracture propagation; no re-meshing of domain is required to model the interaction between hydraulic and natural fractures. XFEM results reveal that the distance and angle of natural fracture with respect to the hydraulic fracture have a direct impact on the magnitude of tensile and shear debonding. The possibility of intersection of natural fracture by the hydraulic fracture will increase with increasing the deviation angle value. At the approaching stage of hydraulic fracture to the natural fracture, hydraulic fracture tip exerts remote compressional and tensile stress on the interface of the natural fracture, which leads to the activation and separation of natural fracture walls.
Part of the book: Fracture Mechanics