降低CO2 驱混相压力的发展现状

将CO₂ 注入油层, 不仅封存了CO₂ , 还可以大幅度提高油气田采收率, 达到CO₂ 减排和油藏高效开发的双赢目的, 受到了相关研究者的广泛重视。如何有效地降低CO₂ 与原油之间的混相压力, 是目前CO₂ 驱提高采收率研究的主要热点和难点之一。文中比较了降低CO₂ 驱混相压力的几种方法, 探索新的亲CO₂ 表面活性剂以降低CO₂ 驱最小混相压力。目前, 降低CO₂ 驱混相压力的主要方法有添加共溶剂法, 但成本比较高; 超临界CO₂ 微乳液法可以降低CO₂ 驱混相压力, 但是目前表面活性剂的研究主要集中在降低油/水界面张力的离子型表面活性剂, 关于降低油/CO₂ 界面张力的非离子表面活性剂还鲜有报道; 亲CO₂ 表面活性剂是降低CO₂ 驱混相压力的一种新探索, 但目前已用的表面活性剂与CO₂ 的亲和性差, 使得CO₂ 对极性较强的大分子物质的溶解能力受到限制。因此, 开发新的亲CO₂ 表面活性剂以达到降低CO₂ 驱混相压力的效果显得尤为关键。

Progress of Miscibility Pressure Reduction of Carbon Dioxide Flooding

A win win purpose of Carbon Dioxide(CO₂ ) emissions and efficient reservoir development can be achieved by injectingCO₂ into reservoir. How to effectively reduce miscibility pressure betweenCO₂ and crude oil, is one of the major hot and difficult problems for enhancing oil recovery byCO₂ flooding. The methods of miscibility pressure reduction usingCO₂ flooding are compared, and new efficientCO₂ philic surfactants are explored. Currently, mixing cosolvent withCO₂ is limited by the price. SupercriticalCO₂ micromulsion can also reduce the miscibility pressure, while the main study is focused on reducing oil/water interfacial tension of ionic surfactants. Nonionic surfactants that can reduce oil/CO₂ interfacial tension are rarely reported. Dissolving capacity of polar compounds inCO₂ is small for the poor compatibility betweenCO₂ and nonionic surfactant. So, the key to reduce miscibility pressure isCO₂ philic surfactant.