Numerical investigation on the hydraulic fracture propagation based on combined finite-discrete element method

Hydraulic fracturing technology is widely used in the exploration of shale gas. Stratum interface is the key element which affect the form of fracture network. This paper proposed a numerical study based on finite-discrete element method to investigate the influence of bedding plane on fracture propagation. A hydraulic fracture would cross the beddings under the high vertical stress difference between a vertical stress and horizontal minimum stress, while a hydraulic fracture propagates along the beddings under a low vertical stress difference. The complex fracture network is more easily generated under the low net pressure, the fracturing fluid leaking into the beddings can act as a lubricant, thus reducing or eliminating the shear strength of the fractures, it is easier for hydraulic fractures to deviate than to cross the weakly cemented and large-aperture bedding plane. Based on the simulation, a mixed fracturing method was proposed to increase the stimulated reservoir volume which was benefit to the generation of fracture network.