Microemulsion formation is an efficient method to select an appropriate surfactant system as well as an optimum condition for such as enhancing oil recovery (EOR). Middle phase or Winsor type III microemulsion exhibits at a minimum or ultralow interfacial tension (IFT) and maximum oil solubilization at which provides the maximum oil recovery through increasing mobility ratio and solubility of trapped oils in the reservoirs. Novel carboxylate-based extended surfactants have been attracted for EOR technology because they perform an ultralow interfacial tension and good stability at high temperature and high salinity conditions. This study aims to formulate the middle phase microemulsion through a binary surfactant system using a carboxylate-based extended surfactant with varying polyethylene oxide number (EO = 2, 4, 6) and a sodium dioctyl sulfosuccinate (AOT) surfactant in heptane, octane, decane and dodecane as a model oil. The microemulsion phase behavior was investigated by varying NaCl concentration known as salinity scan where the optimal salinity (S<sup>*</sup>) can be obtained at the middle phase formation. In addition, the interfacial tension (IFT) was measured to observe their interfacial property of the surfactant with different number of the EO group. The Hydrophilic-Lipophilic Deviation (HLD) equation is applied to estimate the optimal salinity of the binary surfactant system at 25°C. The formation of the middle phase using the carboxylate surfactants is discussed. The correlation between the experimental results and the theoretical HLD estimation is compared through K and Cc values. The findings from this study show that the HLD concept has been used as a guideline to select the appropriate surfactant system as well as an optimal salinity and temperature for microemulsion formulation in EOR application.<br/>

Microemulsion formation by the hydrophilic-lipophilic deviation concept using carboxylate based extended surfactants: Effect of ethylene oxide group

2019 Fall National Meeting

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