油田驱油用CO_(2)泡沫剂体系研究进展

State of the art in research on CO_(2) foam agents for oilfield applications

利用CO_(2)泡沫体系控制气窜和降低气体流度是CO_(2)驱油工艺成功的关键技术。但由于CO_(2)的活性较高,常规表面活性剂形成的CO_(2)泡沫在油藏条件下没有氮气和天然气泡沫那样稳定,因此需要研发具有良好抗温、抗盐和稳定性能的CO_(2)表面活性剂体系。对CO_(2)泡沫剂体系的研发和应用进展进行总结描述,分析不同CO_(2)泡沫用表面活性剂体系的有效性及作用机制,包括基于常规表面活性剂的CO_(2)泡沫体系、CO_(2)气溶性表面活性剂体系、CO_(2)敏感性表面活性剂体系和不同表面活性剂/泡沫稳定剂复配体系,对高效CO_(2)表面活性剂的进一步研发和现场应用提供指导。

CO_(2) foams can be applied to control gas channeling and reduce gas mobility,which is essential for successful CO_(2) flooding processes.However,aqueous CO_(2) solution is acidic,and CO_(2) has high solubility both in water and oil at high pressure,which make CO_(2) foam generated by conventional surfactants not as stable as nitrogen and natural gas foams under oil reservoir conditions.Therefore,it is necessary to develop CO_(2) foaming agents with good temperature resistance,salt resistance and high stability.In this paper,the development and application of CO_(2) foam agents were summarized and described.Based on the interactions among supercritical CO_(2)-water-surfactants and their effects on the stability of CO_(2) foams,the effectiveness and foaming mechanisms of different CO_(2) foam agents were analyzed,including CO_(2) foam based on conventional surfactants,CO_(2) gas soluble surfactants and CO_(2) sensitive foam agents.The synergistic combinations of different surfactants and foam stabilizers were also described,which can provide useful guidance for further development and field applications of highly effective CO_(2) foams.