高温高压CO2/原油界面张力及对驱油效率影响  

Interfacial Tension and Oil Displacement Efficiency between CO_2 and Crude Oil under High Temperature and High Pressure

作　　者：王海涛[1] 王锐[1] 伦增珉[1] 吕成远[1] 骆铭[1] 赵春鹏[1] 潘伟义[1] 

机构地区：[1]页岩油气富集机理与有效开发国家重点实验室,中国石油化工股份有限公司石油勘探开发研究院,北京100083

出　　处：《科学技术与工程》2017年第34期38-42,共5页Science Technology and Engineering

基　　金：国家自然科学基金(51504283);中国石油化工股份有限公司科技开发部项目资助

摘　　要：在油藏温度下,采用ADSA(axisymmetric drop shape analysis)技术测定了不同压力下CO_2/原油动态界面张力和平衡界面张力。界面张力实验发现:原油与超临界CO_2接触的初始阶段存在强烈的扩散作用,原油中的轻质组分被超临界CO_2溶解抽提,并且随着压力的增加,这种溶解抽提作用增强;实验压力范围内,动态界面张力经过25~50 s左右可以达到一稳定值,当P≤19.998 MPa时,动态界面张力曲线波动较大,而当P≥19.998 MPa时,动态界面张力曲线基本保持不变。驱替实验结果表明:CO_2原油体系的平衡界面张力与气驱采收率之间存在关联关系:(1)随着压力升高,体系的平衡界面张力降低,气体突破时的驱油效率和气驱最终驱油效率升高;(2)压力增加到一定值后,体系平衡界面张力降低幅度减小,两种驱油效率增加的幅度也减小;(3)随着压力升高,气驱最终驱油效率与气体突破时的驱油效率之差增大。Dynamic and equilibrium interfacial tensions（ IFT） for different pressures were determined using axisymmetric drop shape analysis（ ADSA） technology under high temperature and high pressure. Many conclusions could be drawn from interfacial tension experiments. The turbulent mixing and light-ends extraction were observed in the initial stage of crude oil contacting CO_2,and the turbulent mixing and light-ends extraction increased as pressure increased. In the range of experimental pressure dynamic interfacial tension could achieve a constant value after 25 ~ 50 s. The fluctuation of dynamic interfacial tension curve when P≤19. 998 MPa was more significant than that when P≥19. 998 MPa. Results of oil displacement experiment showed that there was correlation between interfacial tension and oil displacement efficiency.（1） Equilibrium interfacial tension decreased and gas breakthrough displacement efficiency and final displacement efficiency increased as pressure increased.（2） Decrease extent of equilibrium interfacial tension reduced and increase extent of two kinds of displacement efficiency reduced after pressure achieved a value.（3）The difference between final displacement efficiency and gas breakthrough displacement efficiency enlarged as pressure increased.

关 键 词：ADSA CO2 界面张力 驱油效率 

分 类 号：TE311[石油与天然气工程—油气田开发工程]