低渗透油藏微乳液驱配方优选及微观剩余油研究

STUDY ON MICROEMULSION FORMULA FOR LOW PERMEABILITY RESERVOIR AND MICROSCOPIC RESIDUAL OIL FLOODING MECHANISM

根据正交设计实验优选出最佳微乳液体系,宏观上通过天然岩心微乳液驱油实验,验证微乳液提高采收率的效果;微观上利用光刻玻璃模型进行微乳液驱可视化微观驱油实验,研究微观剩余油的类型和运移过程,通过分析各类剩余油的动用比例研究剩余油的驱油机理。微乳液驱油实验结果表明,与水驱相比,当岩心渗透率从1.78×10^(-3)μm^2增大到29.11×10^(-3)μm^2时,微乳液驱采收率增幅从5.45百分点增大到12.14百分点,与微观实验结果相一致,证明了微乳液可以显著提高采收率。微观剩余油类型分为簇状、柱状、盲端状、油滴状、膜状,其中簇状剩余油和油滴状剩余油的动用比例最高,驱替效果较好,而膜状剩余油的动用比例最低,驱替效果较差。

According to the orthogonal design experiment,the best microemulsion system was selected.The natural rock core displacement tests were conducted to verify the improvement of oil recovery by microemulsion techniques.The lithographic glass model was used to conduct the visualization test of the remaining oil micro-displacement process and its mechanism.The results showed that compared with water flooding,when the permeability of rock core increases from 1.78×10^-3μm^2 to 29.11×10^-3μm^2,the enhanced oil recovery（EOR）by microemulsion is from 5.45 percentage points to 12.14 percentage points,which is consistent with the results of lithographic glass model tests.The five micro-residual oil types are observed：cluster type,column type,blind-end,droplets type,and oil film type.Among them,the flooding proportions of the cluster and droplet residual oil are the highest,the displacement effect is better,and the oil film residual oil is the lowest,and the displacement effect is poor.