Abstract: There is serious gas channeling in the development of Mahu high-temperature tight reservoir. Polymer gel can be used to plug large fractures, which effectively prevents gas channeling from fractures, but it also plugs matrix and micro fractures, resulting in decline in oil recovery. Therefore, a temperature-resistant temporary plugging and profile control agent MHZD was developed and evaluated from the aspects of gelling performance, microscopic morphology, injection performance and plugging capacity. The results show that: The temporary plugging and profile control agent is prepared by 0.6% temperature-resistant cationic polyacrylamide and 0.3% chromium ion cross-linking agent. The plugging system can be stably gelled at 90 ℃ within 38 h, with Grade H gel strength, and the gel can be automatically decomposed into an aqueous solution with a viscosity of 5.63 mPa·s after 7-10 d stabilization. After the injection of temporary plugging agent, the core resistance coefficient is less than 30.000, the maximum breakthrough pressure gradient is greater than 30.000 MPa/m, and the plugging rate and unplugging rate are both greater than 90%. The temporary plugging agent can effectively plug the large pores and recover the remaining oil in the small pores. This study plays an underlying role in plugging against gas channeling and enhancing oil recovery of fractured wells in Mahu tight reservoir.

Key words: temporary plugging agent, gas channeling, resistance coefficient, breakthrough pressure, tight reservoir, Mahu Oilfield