Interfacial Tension Prediction of Water/Oil Mixtures Using Stabilized Density Gradient Theory and Using iSAFT Density Functional Theory

The recovery eciency of crude oil from the reservoir is greatly aected by the interfacial tension(IFT) between water and oil. Large value of interfacial tension would result in oil being trapped in the porous media and hinder recovery eciency. As a result, various enhanced oil recovery techniques including surfactant ooding, steam ooding, etc, have been developed, aiming to reduce the interfacial tension between water/oil and increase the oil production. To better understand the dependence of IFT on temperature and pressure and predict IFT in reservoir conditions, stabilized density gradient theory and interfacial Statistical Association Fluid Theory(iSAFT), one variety of classical density functional theory(DFT), have been applied to study the IFT between water/dodecane, water/toluene, and water/toluene/dodecane at elevated temperatures and pressure. This work contributes to the 9th industrial challenge of predicting water/oil IFT.