Physical simulation and fine digital study of thermal foam compound flooding

According to the similarity criterion of 3D physical simulation of thermal recovery, experimental parameters of 3D physical simulation of steam flooding and thermal foam compound flooding in extra-heavy oil reservoirs of the Gudao Oilfield were calculated, and relevant experiments were carried out. Based on the experimental results, 3D fine numerical simulation was carried out to analyze the steam flooding and thermal foam compound flooding in heavy oil reservoirs. The results show that thermal foam compound flooding could effectively inhibit steam channeling and improve sweep efficiency, and thus enhance the oil recovery in heavy oil reservoirs after steam flooding. Technological parameters of thermal foam compound flooding were optimized according to the results of fine numerical simulation. The optimum injection method is foam-slug injection, the optimal steam injection rate is 25 mL/min, nitrogen injection rate is 1 000 mL/min (standard conditions), the time of foam-slug injection is 1.0 min and the interval between foam-slugs is about 10-20 min during thermal foam-slug injection. At last, the similarity criterion was employed for inversion calculation of the optimization results. Based on the results, optimal field injection and production parameters can be confirmed. The ultimate recovery ratio of thermal foam compound flooding in super-heavy oil reservoirs could reach 42.15%, which is 12.50% higher than steam flooding.