超低渗透油藏CO_2驱提高采收率技术研究与应用

Research on CO_2 Flooding to Increase Oil Recovery in Ultra-low Permeability Oil Reservoir and Application

为进一步提高超低渗透油藏采收率,在研究CO_2驱油机理的基础上,以红河油田长8油藏为目标,通过岩心物理模拟实验对CO_2驱油方式进行了室内评价。实验确定红河油田长8油藏原油与CO_2最小混相压力为20.2 MPa,红河油田长8油藏CO_2驱可以实现近混相驱甚至是混相驱。长岩心室内实验表明CO_2混相驱的驱替压力小于水驱,CO_2/水交替驱可以大幅度提高采收率,相比于水驱可提高28.75%。CO_2驱矿场先导试验表明,CO_2驱油能显著提高超低渗透油藏油井产能,改善油井开发效果,能满足超低渗透油藏开发的需要,具有广阔的应用前景。

To further increase the oil recovery of ultra - low permeability reservoir, the CO, flooding process was evaluated by indoor core physical simulation based on the mechanisms of CO2 flooding on Chang 8 oil reservoir of Honghe Oilfield. The minimum miscibility pressure ofCO2 and crude oil of Chang 8 oil reservoir was determined to be 20.2 MPa, which means that theCO2 miscible flooding could be achieved in Chang 8 oil reservoir of Honghe Oilfield. The indoor long core laboratory experiments showed tha! the displacing pressure of CO2 miscible flooding was hess than that of water flooding. Compared to water flooding, water ahernaling CO2 flooding could inerease oil recovery greatly. The CO2 flooding pilot lest showed that CO2 flooding could significantly increase the oil production capacity of ultra - low permeability reservoir and improve the development effect. CO2 flooding could meet the development requirements of ultra - low permeability reservoir and had broad application prospect.