Abstract:Temporary plugging and diverting fracturing technology is the “trump card” technology for the efficiently stimulate the low-permeability reservoirs that are hard to develop. However, at present, there is lack of study on the evolution law of temporary plugging pressure in the hydro-fracture. In this paper, temporary plugging zone is numerically simulated according to the theory of cohesive zone method (CZM) through a fully coupled stress-seepage finite element model. The main influence factors of the pressure change in the fracture, such as the length of the temporary plugging zone, plugging strength of temporary plugging agent, the injection rate of fracturing fluid, leak-off coefficient of temporary plugging zone is considered in this FEM model. The order of these factors which affect the temporary plugging pressure in the hydro-fracture is determined by the gray relation analysis. The results show that: (1) after the plugging length of the divert agent is up to 5 m, the bearing capacity of the temporary plugging zone will tend to be stable; (2) with the increase of the blocking strength of the temporary plugging agent, the scale of fluid pressure variation will rise rapidly at early stage and then slow down gradually; (3) Increasing the injection rate of fracturing fluid is beneficial to shorten the time of pressure increase by 76.3%, which can effectively improve the capacity of temporary plugging in the hydro-fracture. After the leak-off coefficient of temporary plugging zone decreases to a small value, the pressurization effect is obvious and tends to be stable. According to the gray relation analysis, the order of influence factors of temporary plugging pressure is as follows: injection rate > the length of the temporary plugging agent> plugging strength of temporary plugging agent > leak-off coefficient. The results in this paper have important instruction significance to design the scheme of temporary plugging and diverting fracturing.