直流电动-水动力驱油机理研究

根据物理化学流体动力学理论 ,从多孔介质渗流的毛管模型出发 ,建立了储层条件下电动力水动力耦合公式。利用该理论公式和Buckley Leverett模型 ,探讨了恒速注水电动 水动力驱油机理 ,利用该机理对国内外两个典型实验结果进行了拟合。结果表明 ,在储层条件下 ,由电动力引起的电渗作用是提高水驱油采收率的重要因素之一 ,且电加热作用可以降低原油粘度 ,从而提高水驱油采收率。当直流电场的电位梯度为 7.5V/cm时 ,电加热可以提高原油采收率 1 3%左右 ,而电动力仅可以提高采收率 2 %左右。直流电场作用可以降低水油比 ,施加 5.0V/cm的电场 ,当注入 3倍孔隙体积水时 ,水油比减小了 1 6%。

MECHANISMS OF ELECTROKINETIC-WATER-FLOODING

According to the theory of physicochemical hydrodynamics, an electrokinetic waterflooding coupling model in waterflooding formation is developed. The theoretical modeling and Buckley Leverett modeling are used to study the mechanisms of enhanced waterflooding recovery with electrokinetic waterflooding technique. Two examples of enhanced water flooding recovery with electrokinetic waterflooding technique are stimulated mathematically. The theoretical calculating results show that electrokinetic effect is one of the main factors to enhance waterflooding recovery. Electrical heating can reduce oil viscosity and enhance waterflooding recovery. The enhancement of waterflooding recovery is mainly resulted from the reduction on oil viscosity by electrical heating. The increase of about 13% in waterflooding recovery with electrical heating is obtained when the electrical potential is 7.5 V/cm, and the increase of about 2% in waterflooding recovery with electrokinetic effect is obtained only. The application of the direct current electric field results in a reduction in the WOR. A reduction of about 16% in WOR is obtained after injecting of 3.0 PV water when the applied potential gradient is 5.0 V per centimeter.