Research on Hydraulic Fracturing Crack Propagation Based on Global Cohesive Model

Hydraulic fracturing is currently the main technical means to form complex fracture systems in shale gas development. To explore the influence of fracture dip, fracture length and fracture filling degree on the propagation of hydraulic fractures under complex fracture conditions, this paper establishes a 20 cm × 20 cm two-dimensional numerical model by inserting global cohesive elements and conducting triaxial hydraulic fracturing experiments to verify the model. The results show that the fracture filling degree plays a major role in the fracture pressure and the propagation of hydraulic fractures, while the fracture dip plays a minor role. The experimental results are consistent with the model results in terms of the law, but due to the existence of other natural fractures in the test block, the fracture pressure is smaller than that of this model. This model can provide some theoretical basis and technical support for situations where there are complex natural fractures in hydraulic fracturing.