特高含水油藏CO2微观驱油机制

摘要

根据常见的水驱剩余油类型,提出盲端、孤岛、簇状3种理想剩余油微观模型,应用自主研发的高温高压微观可视化实验装置研究特高含水对CO2与剩余油的微观作用过程影响,建立CO2与油水接触的微观数学模型.结果表明:水的屏蔽作用明显延缓了CO2与原油的微观接触过程,使得混相过程更加复杂化,无论水膜厚度多大,CO2都能穿透水膜溶解于剩余油中;注入压力越高,CO2在的扩散速度越快,达到混相的时间越短;CO2混相驱能够在水驱的基础上进一步提高原油采收率;高含水油藏在实施CO2驱过程中应采用高压低速的注气方式.%On the basis of the residual oil forms after water flooding,three kinds of ideal core models were proposed,which are dead-end model,shaped island model,and cluster model. The microcosmic process influence of extra-high water cut on CO2and residual oil was investigated using a micro-visualization experiment device,which was independent developed under high temperature and high pressure. And the microcosmic mathematic model of CO2-water-oil interaction was established. The results show that water blocking significantly postpones the micro contact process between CO2and trapped oil, which makes the miscible process more complex. And no matter how thick the water film is,CO2can diffuse through the water film into the trapped oil. Higher injection pressure leads to the faster CO2diffusion into oil,which results in achieving more easily miscibility. It is concluded that CO2miscible displacement contributes to oil recovery largely after water flooding. And High-pressure low-rate injection mode of CO2is suggested in extra-high water cut reservoir.