Cyclic steam stimulation (CSS) is a common method for heavy oil reservoir, but the current research on steam channeling in horizontal wells is limited. This study proposes a novel mathematical model based on steam override to predict steam channeling during the CSS process in horizontal wells, focusing on the quantization of the heated region, steam front edge position, and steam channeling time. The model was validated through a 3D physical simulation experiment. The experimental results were broadly consistent with the theoretical predictions. The study finds that steam channel is an upward-curved wedge shape, making it difficult to mobilize the bottom reservoir. The steam channeling time was predicted to be 10.10 min, with an 11.16% error compared to the experimental value of 8.97 min. Furthermore, the introduction of foam increased the oil steam ratio from 1.52 to 1.92. Reducing appropriately the steam injection rate, increasing well spacing, and decreasing steam temperature, together with periodic foam injection, can delay steam channeling. In conclusion, the model offers practical insights for steam channel prediction, which can improve the effectiveness of steam injection strategies in heavy oil reservoirs.

At high cycles of steam huff & puff, oil distribution in reservoirs becomes stronger heterogeneity due to steam channeling. Thermal solidification agent can be used to solve this problem. Its solution is a low-viscosity liquid at normal temperature, but it can be solidified above 80 ℃. The plugging degree is up to 99% at 250 ℃. The sweep efficiency reaches 59.2%, which is 7.3% higher than pure steam injection. In addition, simultaneous injection of viscosity reducer and/or nitrogen foams can further enhance oil recovery. The mechanism of this technology depends on its strong plugging ability, which changes the flowing pattern of steam to effectively mobilize remaining oil. Viscosity reducer and nitrogen foams further expand the sweep range and extends the effective period. Therefore, thermal solidification agent can plug steam channeling paths and adjust steam flowing direction to significantly enhance oil recovery at high cycles of steam huff & puff.