Influence of Joints on Stress Shadow Effect Based on PHF-LSM Model

Using PHF-LSM (permeability-based hydraulic fracture-level set method) hydraulic fracturing calculation model, a rock material model with joint distribution is established. The correctness of the model is verified by comparing the geometric characteristics of fractures and the theoretical solution of induced stress with the simulation result. On this basis, the influence of the presence of joints on the stress shadow effect of hydraulic fractures is analyzed. The simulation results indicate that: the displacement difference of the outermost node in the equivalent fracture region should be used as the equivalent fracture opening in the PHF model based on the dispersion fracture model; the existence of joints will affect the change of water pressure in the process of fracture water injection, and will increase the equivalent fractures opening; a larger joint incidence angle and a smaller joint height from the water injection point will produce greater induced stress, and change the direction of the minimum principal stress, resulting in a stronger stress shadow effect and enhanced fracture deflection.