注CO2对高温高压条件下油-地层水体系界面张力的影响  

Effect of CO2 injection on interfacial tension of oil-formation water system at high temperature and pressure

作　　者：王欣[1,2] WANG Xin(Sinopec Key Laboratory of Marine Oil&Gas Reservoirs Production,Beijing 100083,China;Sinopec Exploration&Production Research Institute,Beijing 100083,China)

机构地区：[1]中国石油化工集团公司海相油气藏开发重点实验室,北京100083 [2]中国石化石油勘探开发研究院,北京100083

出　　处：《热力发电》2021年第1期123-128,共6页Thermal Power Generation

基　　金：国家重大科技专项(2016ZX05048003)。

摘　　要：目前对于CO2-原油界面张力特征研究较多,但是对于原油-CO2地层水体系相界面作用特征的研究较少。本文采用轴对称悬滴形状分析技术分析了不同CO2饱和度对原油-地层水平衡界面张力的影响,以及原油-饱和CO2地层水与原油-地层水平衡界面张力的变化。同时,对CO2通过油-水界面从油滴中提取轻烃组分的现象,进行了研究和分析。结果表明:原油-饱和CO2地层水的平衡界面张力随压力的增加而降低,随压力的增加,体系的溶解和扩散越来越明显;油与饱和CO2地层水之间发生介质交换,出现部分混溶现象;在该体系压力高于压力阈值17.09 MPa时,CO2溶解度增加趋势变缓,原油-饱和CO2地层水平衡界面张力降低缓慢基本保持不变。实际生产中,在低于体系阈值压力时,提高CO2含量能够有效地降低界面张力;高于阈值压力后,继续增加CO2含量对体系平衡界面张力作用不大。该研究可为节约CO2驱替成本提供参考。At present,there are many researches on the interfacial interaction between CO2 and oil,but few on the interfacial interaction of CO2-water-oil.In this paper,axisymmetric drop shape analysis method is used to analyze the influence of different CO2 saturations on the interfacial tension of crude oil-formation water and the change of the interfacial tension between crude oil-carbonate water and crude oil-formation water.In addition,the extraction of light hydrocarbon components from oil drops by CO2 through the gas-water interface is studied.The results show that,the equilibrium interfacial tension of crude oil-carbonated water system decreases with the increase of pressure,and the dissolution and diffusion of the system becomes more and more obvious with the increase of pressure.The medium exchange occurs between oil and carbonated water,and the phenomenon of partial miscibility occurs.When the pressure is higher than the pressure threshold of 17.09 MPa,the increasing trend of CO2 solubility becomes slower,and the interfacial tension of crude oil saturated CO2 formation water decreases slowly and remains unchanged.In practical production,when the pressure is lower than the system threshold pressure,increasing CO2 content can effectively reduce the interfacial tension. When the pressure is higher than the threshold pressure,increasing CO2 content has little effect on the equilibrium interfacial tension.

关 键 词：界面张力 CO2驱 原油-饱和CO2地层水 原油-地层水 多相界面 采收率 

分 类 号：TE311[石油与天然气工程—油气田开发工程]