Investigation on the fracture morphology of reciprocating fracturing in horizontal wells

Hydraulic fracturing technology of horizontal wells is a crucial stimulation measure in shale reservoirs. The stress field will change during fracture propagation, and the subsequent fracture shape will be uncontrollable. Fractures initiated mainly affect the subsequent fractures through stress shadows, used to control the propagation of fractures during reciprocating fracturing. This paper establishes a numerical model for reciprocating fracturing based on the extended finite element. The reliability of the model is verified based on the stress interference theory. Numerical simulations of conventional sequential fracturing and three kinds of reciprocating fracturing were performed. The simulation results show that the accumulative fracture deflection angles are 160°, 76°, 88°, and 156° of the four fracturing methods, and we find that reciprocating fracturing could control the fracture morphology effectivity. When the fracture morphologies are controllable, the maximum ratio of fracture length to fracture spacing using reciprocating fracturing is 29.17% better than conventional sequential fracturing. This research can provide theoretical support for hydraulic fracturing fracturing method selection.