Experimental Investigation of Steam Channeling Mitigation Strategies in Thin-Bed Heavy Oil Reservoirs Post-thermal Recovery

Heavy oil resources account for more than 20% of China’s total oil resources, but steam channeling often leads to ineffective circulation of injected steam, thereby reducing oil recovery. Aiming at the problems of large temperature variation range after high-round huff and puff and difficult plugging after steam channeling in thin-layer unconsolidated sandstone heavy oil reservoirs, this paper first carried out crystallization simulation calculation and static crystallization experiment, and determined the thermal solid plugging agent system suitable for water plugging and channeling sealing in target reservoirs. Then, the plugging effect of gel polymer and thermosetting plugging agent system in thermosetting plugging agent system was evaluated by core flow experiment. Finally, through the high temperature and high pressure visual physical simulation experiment, the channeling channel was identified, the steam channeling phenomenon was described, and the plugging effect and oil increasing effect of the thermosetting plugging agent system were evaluated. The experimental results showed that the thermosetting plugging agent system did not react at 60 ℃, and the critical temperature of crystallization was controlled at 80 ℃. The pore plugging rate of the system was 1.01%~1.59%, and the core plugging rate could reach 75%~90%. The thermosetting plugging agent system first entered the high permeability channeling zone. After the subsequent injection of steam, the steam promoted the system to effectively block the channeling channel and change the subsequent steam flow direction. The injection of thermal solid plugging agent system after steam channeling of steam flooding could effectively block the longitudinal and plane steam channeling channels, and improve the longitudinal recovery degree and plane recovery degree by 24.79% and 17.06% respectively.