This study explores the impact of salinity on fluid replacement during imbibition-driven oil recovery through a series of core self-imbibition experiments.By integrating key parameters such as interfacial tension,cont...This study explores the impact of salinity on fluid replacement during imbibition-driven oil recovery through a series of core self-imbibition experiments.By integrating key parameters such as interfacial tension,contact angle,and oil displacement efficiency,we systematically examine how variations in salinity level,ion type,and ion concentration affect the imbibition process.The results demonstrate that the salinity of the injected fluid exerts a strong influence on the rate and extent of oil recovery.Compared with high-salinity conditions,low-salinity injection,particularly below 5000 mg.L-1,induces pronounced fluctuations in the replacement rate,achieving the highest recovery at approximately 1000 mg·L-1.The interplay between interfacial tension and displacement efficiency is jointly governed by both ion type and concentration.Moreover,changes in ionic composition can alter rock wettability from oil-wet toward water-wet states,thereby enhancing imbibition efficiency.Among the tested ions,Mg2+and SO4²at low concentrations were found to be especially effective in promoting oil displacement.展开更多
基金the National Natural Science Foundation of China(Grant Nos.52374038 and U23B2089)Innovation Capability Support Program of Shaanxi(Program No.2024ZC-KJXX-064).
文摘This study explores the impact of salinity on fluid replacement during imbibition-driven oil recovery through a series of core self-imbibition experiments.By integrating key parameters such as interfacial tension,contact angle,and oil displacement efficiency,we systematically examine how variations in salinity level,ion type,and ion concentration affect the imbibition process.The results demonstrate that the salinity of the injected fluid exerts a strong influence on the rate and extent of oil recovery.Compared with high-salinity conditions,low-salinity injection,particularly below 5000 mg.L-1,induces pronounced fluctuations in the replacement rate,achieving the highest recovery at approximately 1000 mg·L-1.The interplay between interfacial tension and displacement efficiency is jointly governed by both ion type and concentration.Moreover,changes in ionic composition can alter rock wettability from oil-wet toward water-wet states,thereby enhancing imbibition efficiency.Among the tested ions,Mg2+and SO4²at low concentrations were found to be especially effective in promoting oil displacement.
