大庆油田三元复合驱驱油效果影响因素实验研究

通过岩心物理模拟实验及微观驱油实验,分析了界面张力、三元体系粘度、乳化油滴产生及岩石润湿性对三元复合驱驱油效果的影响规律和影响机理。研究结果表明,油水间平衡、动态界面张力大幅度降低可有效提高三元复合驱驱油效率,进行三元复合驱时,油水界面张力须降到10^-3mN/m数量级;增加体系粘度能够扩大三元复合驱的波及体积,水油粘度比大于2是三元复合驱提高采收率幅度达到20%的必要条件;乳化的油滴产生是三元复合驱提高驱油效率的主要形式,油水界面张力越低、驱替体系粘度越大,乳化油滴的产生能力越强,驱油效果越好;三元复合驱能够驱替亲油岩石表面的油膜,促进岩心润湿性由亲油向亲水转化。

Experimental study on influential factors of ASP displacement efficiency in Daqing Oilfield

On the basis of core physical simulation experiment and micro-displacement experiment, influential rule and mechanism of interfacial tension, viscosity of ASP system, formation of emulsified oil droplet coalescence and reservoir rock wettability on ASP displacement efficiency have been analyzed. The result showes that improving water/oil balance and reducing dynamic interfacial tension can greatly increase ASP displacement efficiency and oil/water interfacial tension must be lower than 10^-3 mN/m magnitude order by ASP flooding. In addition, increasing viscosity of ASP system can enlarge ASP swept volume, with necessary condition of water/oil viscosity ratio more than 2 for improving oil recovery by 20% by ASP flooding. As emulsified oil droplet formation is the main way to enhance ASP displacement efficiency, the lower water/oil interfacial tension is, the higher viscosity of displacement system lis; the easier producing emulsified droplet energy is, the better displacement efficieney is. Moreover, ASP flooding can displace oil-film on the surface of oil-wet rock and change rock wettability from oil-wet to water-wet.