Physical simulation experiments on CO2 injection technology during steam assisted gravity drainage process

This study aimed to further improve the development effect of steam assisted gravity drainage (SAGD) in consideration of the current development situation of extra-heavy oil reservoir in the Guantao Formation in Du84 Block of Liaohe oilfield, China. Two-dimension physical simulation experiments were carried out to improve the production mechanism and feasibility of SAGD process through CO2 injection. The results showed that it was feasible to apply CO2-assisted SAGD for the development of extra-heavy oil reservoir in the Guantao Formation. The injected CO2 had a dual effect of non-condensate gas and solvent during SAGD process of extra-heavy oil reservoir. According to the analysis of temperature field data, CO2 injection contributed to lateral expansion of SAGD steam chamber and increased the transverse wave and volume of steam. Additionally, CO2 injection significantly improved reservoir recovery factor, oil steam ratio, and oil production rate of SAGD. The influence of CO2 amount on SAGD development was further analyzed, and the CO2-to-steam injection ratio was preliminarily optimized to be 20%. ©, 2014, Science Press. All right reserved.