Interfacial composition and solubilization of microemulsion systems containing mixed surfactants C12mimBr and Brij35: effects of surfactant composition, temperature, and salinity

Advances of microemulsion and its applications for improved oil recovery

Microemulsion, because of its excellent interfacial tension reduction and solubilization properties, has wide range of applications in the petroleum industry, especially in improved oil recovery (IOR). Herein, the concept, types and formation mechanism of microemulsion were primarily introduced. Then, the preparation and characterization methods were illustrated. Additionally, several effect factors were elaborated specifically based on the composition of microemulsion. Finally, the application of microemulsion in IOR was addressed, including IOR mechanism analysis based on sweep efficiency and displacement efficiency, injection method (microemulsion flooding, in-situ microemulsion formation) and field tests. Furthermore, the current challenges and prospects of microemulsion on IOR were analyzed.

Composition and Solubilization of the Microemulsion Systems Containing Triton X-100: Effects of Aqueous Composition and Oil-Water-Ratios

The composition and solubilization of the optimum microemulsion systems containing Triton X-100/pentan-1-ol/aliphatic hydrocarbon/water were studied with the ∊-β fishlike phase diagram method. The solubilities of the alkanol (S A), the mass fractions of the alkanol in the interfacial layer (AS ) and the optimum solubilization parameters (SP∗) of the microemulsion systems with different aqueous phases (salt, acid, alkali) and with different α values were obtained and discussed. The SP∗ values increase significantly with the cation radius of the chlorides (NaCl, KCl, CsCl), but decrease slightly with the anion radius of the sodium halides (NaCl, NaBr, NaI). However, SP∗ values decrease with the increased salinities and NaOH contents. The trend was reversed for the acid systems. When the oil-water ratio (α) increases, the S A and A S values significantly increase, while the SP∗ values increase slowly. As the length of the carbon chain of the alkane molecules increases, both the S A and A S values increase, while the SP∗ values decrease significantly.

A Comparison Study on the Phase Behavior and Solubilization between Cn(Bim)2-2Br-Butyric Acid and CnmimBr-Butyric Acid Microemulsion Systems

The solubility, interfacial composition and solubilization ability of microemulsions containing gemini 1,4-bis(3-alkylimidazolium-1-yl) butane bromide [Cn(Bim)2-2Br]/butyric acid were studied and compared with that of microemulsions containing 1-alkyl-3-methylimidazolium (CnmimBr)/butyric acid. The solubilities of butyric acid (SA), and the mass fractions of butyric acid in the interfacial layer(AS) decrease, while the solubilization parameters (SP*) increase with the increase in the carbon chain length of the surfactants in Cn(Bim)2-2Br based and CnmimBr based microemulsions. A comparison of the gemini Cn(Bim)2-2Br microemulsions with CnmimBr microemulsions indicates that the values of SA and AS are in the order: Cn(Bim)2-2Br < CnmimBr, while SP* values are Cn(Bim)2-2Br > CnmimBr. With salinity increasing, the values of SA and AS decrease, while SP* values increase. With the increase in the alkyl chain length of the oil molecules, the SA values increase, AS and SP* values decrease. Temperature has less influence on the values of SA, AS and SP* of microemulsions containing Cn(Bim)2-2Br/butyric acid.