关键词: 稠油油藏, 物理模拟, 蒸汽吞吐, 二氧化碳吞吐技术, 油藏开采机理, 现场试验

Abstract: The cyclic carbon dioxide injection technology to improve heavy oil production after steam soak was studied by physical simulation. The mechanisms of cyclic carbon dioxide injection were investigated. The results show that injection of carbon dioxide into heavy oil reservoir in the late steam soak period can increase expansion energy and decrease oil viscosity and also demulsify the emulsion formed in the steam soak process. In general, carbon dioxide dissolved in the heavy oil can reduce oil-water surface tension and result in breakdown of emulsion. Also, the injected carbon dioxide can change oil-water relative permeability and lower the remaining oil saturation. The field pilot test shows that cyclic carbon dioxide injection after steam soak is successful in technology and has the economic benefits. Both physical simulation and pilot test show that cyclic carbon dioxide injection technology is economically feasible to improve the development results after multi-cycle steam soak for heavy oil reservoir.

Key words: heavy oil reservoir, physical modeling, steam soak, cyclic carbon dioxide injection technology, oil recovery mechanism, field test