油水乳化能力对油膜驱替的影响

为深化油膜驱替机理认识,开展油膜驱替实验。以综合反映乳化速度和乳化量的乳化系数量化表征油水乳化能力。针对实验用低黏和中黏原油,筛选出具有强乳化能力-超低界面张力、强乳化能力-低界面张力和弱乳化能力-超低界面张力3种不同性质的驱油剂,并进行玻璃棒束油膜驱替实验。实验结果表明,对于低黏原油,乳化系数分别为0.667和0.706的强乳化能力驱油剂,不论其界面张力是否达到超低,其驱替效率都约为90%,而乳化系数为0.244的弱乳化能力-超低界面张力驱油剂的驱替效率不足70%;对于中黏原油,乳化系数分别为0.534和0.602的强乳化能力驱油剂,不论其界面张力是否达到超低,其驱替效率都约为83%,而乳化系数为0.258的弱乳化能力-超低界面张力驱油剂的驱替效率不足65%。研究结果表明,油水乳化能力是对油膜驱替起决定作用的性能指标。

Effect of oil-water emulsification capability on oil film displacement

In order to have a better understanding of the mechanism of oil film displacement,the oil film displacement ex periments are conducted.Considering the effects of emulsifying speed and emulsification amount,the emulsification index(EI)is used to quantitatively characterize the emulsification capability of the chemical flooding agents.For the low and me dium viscosity oil used in experiments,three kinds of oil displacement agents are screened,which have the strong emulsifi cation capability and ultra-low interfacial tension(IFT),strong emulsification capability and low IFT,and weak emulsifica tion capability and ultra-low IFT,respectively.And then,the three kinds of oil displacement agents are used to conduct the oil film displacement experiments based on the glass rod bundle model.For the low viscosity crude oil,the oil film displace ment efficiencies of the oil displacement agents with higher emulsification capability(EI are 0.667 and 0.706 respectively)are about 90%no matter the IFT of displacement agents is ultra-low,while the oil film displacement efficiency of the oil displacement agent with weak emulsification capability and ultra-low IFT(EI=0.244)is less than 70%.For the medium viscosity oil,the oil film displacement efficiencies of the oil displacement agents with higher emulsification capability(EI are 0.534 and 0.602 respectively)are about 83%no matter the IFT of oil displacement agents is ultra-low,while the oil film displacement efficiency of oil displacement agent with weak emulsification capability and ultra-low IFT(EI=0.258)is less than 65%.The research results show that the oil film displacement efficiencies mainly depend on the emulsification capa bility of the oil displacement agents.