低渗透油田用CO_2气溶性泡沫体系研发及性能评价

Development and performance evaluation on CO_2-soluble surfactant foam system for low permeability reservoir

利用可视化高温高压泡沫仪筛选出具有良好CO_2泡沫性能的表面活性剂,在醇类等共溶剂的辅助下,评价其在超临界CO_2中的溶解性能;利用高温高压岩心驱替实验装置,评价CO_2气溶性泡沫体系提高采收率的能力。结果表明,所筛选的非离子型表面活性剂N-P-12在125℃高温条件下可以产生具有一定稳定性的CO_2泡沫,醇类等共溶剂的加入可以明显提高其在超临界CO_2中的溶解度。CO_2气溶性泡沫体系驱油过程中阻力因子呈先增大后减小的趋势,生成的泡沫对体系流动起到流度控制的作用,且较常规CO_2泡沫能够显著提高原油采收率,最终采收率高达92.50%。

The surfactants with good CO2 foam performance were screened out by high-pressure and high-temperature visualized foam device.The solubility of the systems in supercritical CO2 were evaluated by using alcohols as co-solvents.The ability of EOR of CO2-soluble surfactant foam was tested by high-temperature and high-pressure core displacement experimental device.The results show that the selected nonionic surfactants N-P-12 have good CO2 foam stability at high-temperature condition of 125℃,and the addition of alcohol as co-solvents could significantly increase the solubility of the surfactants in the CO2.During the CO2 foam flooding,the resistance factor may increase first and then decrease,and the generated foam may play the role of mobility control in the system.Moreover,CO2 foam based on CO2-soluble surfactant is more efficient on enhancing oil recovery than the conventional CO2 foam,and the ultimate oil recovery is raised up to 92.50%.