Study On The Gas Channeling Mechanism And Sealing Technology Of CO₂ Flooding

Small viscosity and reservoir heterogeneity both the main influencing factors of gas channeling in the process of CO2 flooding and these factors have serious impact on the displacement effect of CO2. In this paper, the theoretical analysis and the experimental method are combined to analyze the main factors that affect gas channeling. mechanism are analyzed by establishing the theoretical model and solving model and study of sealing technology by laboratory experiment.So we compared three kinds of sealing technology(Profile control, flooding control ,foam flooding).The results show that the gas channeling mechanism: (1) The stronger the heterogeneity of the reservoir, the earlier the gas production, the more serious the gas channeling, and the higher the remaining oil saturation. (2) The displacement ratio is more close to 1, the displacement effect is better, and the remaining oil saturation is smaller. (3) The experimental results are consistent with the theoretical results.The results of indoor physical simulation experiment of sealing channeling:(1) Profile control and displacement control and flooding have a significant improvement in the oil displacement effect, but the foam flooding effect is not as good as the first two. (2) The final recovery ratio increased from 10 to 20 percentage points after the profile control, and the greater the increase of the injection, the greater the recovery. (3) The regulation and control method is the best way of sealing, the recovery rate is the largest, and the final recovery ratio is 14.73 to 23.38 percentage points higher than that of carbon dioxide flooding.(4) Compared with the first two kinds of sealing technology, foam flooding plugging technology is weak,and the final recovery ratio is less than 10 percentage points.To sum up, it is correct and effective to solve the problem of gas channeling from the gas channeling mechanism.It is effectively improved oil recovery.