Ultralow Interfacial Tension for Enhanced Oil Recovery at Very Low Surfactant Concentrations

Abstract

The interfacial tension (IFT) between alkanes and several individual surfactants and their mixtures has been investigated, using three kinds of alkyl hydrocarbons: decane, dodecane, and tetradecane. For individual and mixed surfactant systems, critical micelle concentrations and areas per molecule at the hydrocarbon-aqueous solution interface were calculated; for the mixed surfactant systems, betasigma(LL), the molecular interaction parameter at the hydrocarbon-aqueous solution interface, and beta(M), the molecular interaction parameter in mixed micelle formation, were calculated. It was found that IFT in the 10(-3) mN/m (ultralow) range can be obtained at surfactant concentrations below 0.05 wt % and even at concentrations below 0.01 wt %, when mixtures of certain surfactants are used at the proper ratio. Surfactants with branched-chain alkyl groups show a much better IFT reduction effectiveness than those with straight-chain alkyl groups. Contrary to what has been observed at the air-aqueous solution surface, mixtures of two homologues with two hydrophobic groups show significant molecular interactions, with both betasigma(LL) and beta(M) having negative values in the 4-5 range in some cases, with the betasigma(LL) value more negative than beta(M). The relationship between micellar shape and ultralow IFT was investigated by calculating the critical packing parameter of the surfactants. It was found that ultralow IFT between the surfactant mixtures and the three hydrocarbons investigated could reach ultralow (<10(-2) mN/m) values when the critical packing parameter is very close to 1.

A review on applications of nanotechnology in the enhanced oil recovery part A: effects of nanoparticles on interfacial tension

“…However, such surfactants are expensive. The use of a hydrophilic surfactant mixed with a relatively lipophilic surfactant or a new surfactant was also investigated [73][74][75]. However, studies on SP flooding only focused on the screening and evaluation of the polymer and surfactant and their interaction.…”

“…This results in increasing the interface consequently makes a considerable contribution to reducing IFT. This means that capillary forces considerably decrease and capillary number will strongly be increased [75]. In fact, both nanoparticles and surfactants help each other to remain stable and to contribute to keeping the formed emulsions stable.…”

A review on applications of nanotechnology in the enhanced oil recovery part B: effects of nanoparticles on flooding

“…The observed reduction in interfacial tension and wettability is the result of nanoparticle present at the interfacial layers. As a result, using nanoparticles shows a 19 % increase in oil recovery when compared to surfactants used alone [45].…”

Effect of viscosity and interfacial tension of surfactant–polymer flooding on oil recovery in high-temperature and high-salinity reservoirs

“…However, such surfactants are expensive. The use of a hydrophilic surfactant mixed with a relatively lipophilic surfactant or a new surfactant was also investigated (Rosen et al 2005;Aoudia et al 2006;Cui et al 2012). However, studies on SP flooding only focused on the screening and evaluation of the polymer and surfactant and their interaction.…”