CO_2与油水的相互作用对驱替过程的影响研究

Effects of Interaction Among CO_2,Oil and Water on Displacement

二氧化碳注入过程中,CO2与油水发生的相互作用将会对驱替过程产生一定的影响。通过不同压力条件下CO2在油水中的溶解实验,结合经典计算模型,得到了溶解CO2后的水、油黏度变化规律。通过不同含水率条件下的油水乳化实验,考察了溶解CO2前后油水乳化程度(以乳化带体积占油水总体积的百分比表示)。实验结果表明,CO2在油、水中溶解后,地层水的黏度增大,原油的黏度减小,CO2的溶解有利于改善水油黏度比,且初始压力从0.1MPa增至6MPa时,水油黏度比增大至原来的4.672倍。溶入CO2的油水体系的乳化程度远远大于未溶入CO2油水体系的,且含水率为40%时,碳酸水/原油体系的乳化程度可达96.43%。CO2与油水的相互作用,有利于改善水驱微观驱油效率,扩大气驱宏观波及效率,提高原油采收率。

The interaction among CO2,oil and water has significant effects on the water flooding during the process of CO2 injection.Based on the classical theoretical models,the viscosities of water or oil were obtained through the experiment of CO2 dissolution in water or oil at different pressures.The emulsifying degree（denoted as the ratio of the emulsion band volume to the total volume） of oil/water system before and after CO2 injection with different water cut was investigated.The results showed that the viscosity of the water phase increased,while the viscosity of the oil phase decreased after CO2 injection.Furthermore,the water-oil viscosity ratio could be improved when CO2 dissolving in water/oil system,especially,the water-oil viscosity ratio increased 4.672 times than that without CO2 injection when the pressure increased from 0.1 MPa to 6 MPa.The dissolution of CO2 could promote the emulsion process of water and oil and the extent of emulsification could be up to 96.43% at the water cut of 40%.The interaction among CO2,water and oil could improve microscopical oil displacement efficiency and enlarge macroscopical sweep efficiency.