Experimental study of the temporary plugging capability of diverters to block hydraulic fractures in high-temperature geothermal reservoirs

The effective plugging of artificial fractures is key to the success of temporary plugging and diverting fracturing technology, which is one of the most promising ways to improve the heat recovery efficiency of hot dry rock. At present, how temporary plugging agents plug artificial fractures under high temperature remains unclear. In this paper, by establishing an improved experimental system for the evaluation of temporary plugging performance at high temperature, we clarified the effects of high temperature, injection rate, and fracture width on the pressure response and plugging efficiency of the fracture. The results revealed that the temporary plugging process of artificial fractures in hot dry rock can be divided into four main stages: the initial stage of temporary plugging, the bridging stage of the particles, the plugging formation stage, and the high-pressure dense plugging stage. As the temperature increases, the distribution distance of the temporary plugging agent, the number of pressure fluctuations, and the time required for crack plugging increases. Particularly, when the temperature increases by 100 ℃, the complete plugging time increases by 90.7%.