Analytical model for predicting initiation pressure of intra-fracture temporary plugging and diverting fracturing

Intra-fracture temporary plugging and diverting fracturing are important technical means of improving the complexity of fractures in unconventional oil and gas reservoirs. The key to this technology is whether diverted fractures can be formed; therefore, a prediction model of the fracture initiation pressure needs to be established. Owing to the plugging effect of the temporary plugging agent, net pressure in the fractures before and after the temporary plugging section is discontinuous, which affects the induced stress field distribution around the fractures. However, it is difficult for the conventional induced stress calculation model to solve the induced stress field quickly when the pressure in the fracture is discontinuous. In this study, based on the superposition principle, an analytical model for the prediction of the initiation pressure considering discontinuous pressure is established and the initiation law of diverted fractures is analyzed. The simulation results show that the initiation position of the new fracture is at the temporary plugging position. The closer the temporary plugging position is to the fracture tip, the more difficult it is for new fractures to initiate.