The Influence of Temperature, Pressure, Salinity, and Surfactant Concentration on the Interfacial Tension of the N-Octane-Water System

Abstract

An elaborate experimental study was conducted for the determination of the interfacial tension (IFT) values for a n-octane/water system for a wide range of experimental conditions of temperatures, pressures, and salt concentrations that exist in a natural oil reservoir. Three different surfactants were used in the analysis: dodecyl benzene sulfonic acid sodium salt, sodium dioctyl sulfosuccinate, and hexadecyl trimethyl ammonium bromide. The measured IFT values were correlated linearly to pressure (P), temperature (T), and salt concentration (CB) in the aqueous phase. There was an almost 20-fold reduction noticed in the IFT values with the addition of surfactants. This behavior was best related by an exponential pexpression in terms of the surfactant concentration (CS) as given below: The experimental data for the three surfactants can be represented independently by the above correlation. The absolute average percentage error was always less than 7% for the different data sets considered. Keywords: Enhanced oil recoveryInterfacial tensionSolubilityConcentrationRegressionn-Octane Acknowledgment The authors would like to thank the research administration at Kuwait University for partially sponsoring this research under grant EC072. We would also like to thank Prof. El-Gibaly for many helpful discussions at the beginning of this work.