30 m填砂管中复合驱油体系特性对驱油效率的影响

为更加准确地模拟油藏在长时间、大距离条件下的驱油过程,建立了一套长30m的驱油物理模型,通过分析驱油过程中沿程压力变化来考察驱油效果。实验结果表明,从注入ASP驱油剂开始计算,注入0.5PV时,ASP的作用才开始显现,0.9PV时的效果最好,1.4PV后效果开始消失;界面张力仅在较短的时间含油较少的前10%距离内能够达到超低状态,为采出程度的提高所做的贡献仅为7.7%。可见,超低界面张力所作出的贡献是有限的;驱油效率较高时,整个长填砂管中的黏度保留率相对较高,且黏度保留率最高值所处位置残余油饱和度也较高,为驱油效率的提高做了主要贡献。可见,超低界面张力状态并不是采收率提高不可或缺的因素,黏度及其保留率的作用是至关重要的。

Experiment research on the effect of ASP system property on oil displacement efficiency in 30 m sand filling tube

For simulating the long distance flooding process of real reservoir more accurately, the paper established a length of 30 meters flooding physical model. The model has multiple measurement points and sampling points along the way to monitor the changes of pressure and the properties of displacing agent in course of flooding. The results showed that:from the beginning of ASP flooding, when injected 0.5PV, the effect of ASP began to appear; when injected 0.9PV, the ASP showed the best results, when injected 1.4PV, the effect of ASP began to disappear; the interfacial tension could achieve ultra low status only in a short time and in the beginning of 10% distance, the contribution of improvement recovery degree is only 7.7%, it means that the contribution of ultra-low interfacial tension is limited. When the oil displacement efficiency is higher, the viscosity retention rate in the entire length tube is relatively higher, and residual oil saturation is also higher when the viscosity retention rate is the highest, which has made the major contribution to the oil displacement efficiency. Thus the ultra-low interfacial tension is not an indispensable factor to improve oil recovery, but the viscosity and its retention rate are crucial and should be taken seriously enough.