降低CO2驱油最小混相压力新方法

从CO2气体着手,探索液化气对CO2混相驱油MMP的影响,研究降低最小混相压力的方法,并利用自主研制的高温高压界面张力仪,采用悬滴界面张力法测定CO2与原油的界面张力。结果表明,向CO2中加入一定比例液化气可以达到降低CO2混相驱油最小混相压力的目的,而且不同含量CO2与相应MMP近似呈线性关系。据此可根据地层压力设计CO2混相驱油方案,优化CO2比例,从而达到CO2混相驱提高原油采收率的目的。

A New Method of Reducing the Miscible-phase Pressure of CO2 Flooding

CO2 miscible flooding can greatly enhance oil recovery,but CO2 miscible flooding in most oil field is hard to implement because of the miscibility pressure,which even higher than the formation pressure.Therefore,a new method to reduce the minimum miscibility pressure must be sought.This paper targets at CO2 gas,to explore how liquid gas effect the minimum miscibility pressure,and gets a new method to reduce the minimum miscibility pressure.It uses the high temperature and pressure interfacial tension instrument manufactured by ourselves to evaluate interfacial tension data of CO2 and reservoir crude oil following the pendant-drop method.Result shows that adding a certain proportion of liquid gas to CO2 can reduce CO2 miscible flooding minimum miscibility pressure,and different content of CO2 and the corresponding MMP approximate linear relation.Then a CO2 miscible flooding plan can be designed according to the formation pressure,and the proportion of CO2 can be optimized,thus the CO2 flooding to enhance oil recovery can be achieved.