Rock Crack Propagation Mechanism of Oriented Perforation Hydraulic Fracture under Different Perforation Parameters

In order to obtain the mechanism of crack propagation of oriented perforation hydraulic fracture and its effect on mechanical properties of rock samples, an experimental study on hydraulic fracture of rock samples without confining pressure was carried out. The confining pressure ratio coefficient was defined, and oriented perforation hydraulic fracture was numerically simulated based on the extended finite element method so as to explore the comprehensive influence of different perforation parameters. The results demonstrated that the crack initiates and propagates along the direction of perforation azimuth angle, and the crack of oriented perforation is slightly wider than that of non-oriented perforation. The difficulty of crack initiation and turning increases with the perforation azimuth angle and decreases with the confining pressure ratio coefficient. Crack initiation and propagation are mainly driven by tensile stress, and the crack initiation pressure increases with the perforation azimuth angle and the confining pressure ratio coefficient.