Advances and key techniques of temporary plugging and diverting fracturing

Temporary plugging and diverting fracturing (TPDF) is one of the important stimulation means to increase production when developing unconventional oil and gas resources. By compiling the literature on TPDF technique at home and abroad, the development of TPDF technique was summarized from three aspects: mechanism, material and process. Firstly, TPDF included three key steps: transport of the temporary plugging agent, plugging process, and fracture diverting. The divergent behavior in transport of different temporary plugging agent particles affected the subsequent plugging process, which in turn affected the opening of new fractures, and all three are closely related. Secondly, various types of temporary plugging agents are applied in the field, including solid particles, fibers, gels, foams, etc. Suitable temporary plugging agents need to be selected according to the reservoir characteristics, especially considering their temperature resistance, degradability and intensity. Presently, degradable particles and fiber temporary plugging agents were the mainstream development trend. Finally, the TPDF technique had a wide range of application scenarios, and its effectiveness had been confirmed by various monitoring methods. During the operation, different filling methods need to be adopted according to the difference in temporary plugging agent types, and the amount and timing of temporary plugging agent can be optimized and designed through various advanced technical means such as fiber optics outside the pipe and high frequency pressure monitoring. With the application and promotion of these advanced technologies, the TPDF operation will finally realize real-time regulation and optimization.