Laboratory Evaluation of a Crude-Oil-Sulfonate/Nonionic-Cosurfactant Micellar Fluid

Abstract

Phase behavior, interfacial tension (1FT) measurements, fractionation studies, and core tests have been used in the formulation of a crude-oil-sulfonate (CROS)/ethoxylated-alcohol micellar fluid for application in a changing ionic environment that attains a relatively high hardness concentration as a result of ion exchange. By varying the hydrophile/lipophile balance (HLB) of the nonionic cosurfactant, phase behavior can be shifted from lower to upper phase and the optimum can be found. It is shown that the solubilization of oil and brine and the value of the optimum can be controlled further by blending different nonionic surfactants with CROS samples whose properties were altered by controlling variables in the manufacture. Effects of such system variables as surfactant and hardness concentration and the ratio of CROS/nonionics have a significant effect on phase behavior. The 1FT vs. solubilization parameter correlation was in reasonable agreement with that of Huh 1 and is shown.to hold over a wide range of surfactant and hardness concentrations, but the intercept is different for each CROS/nonionic pair. 1FT's and phase behavior from core-test effluents are shown to agree with the phase-behavior studies. Fractionation phase-behavior studies indicate that chromatographic separation will affect the process significantly only if oil is inefficiently displaced; this is supported by core tests. Excellent oil recovery was attained in Berea over a wide range of concentrations and HLB's, and with small slugs. Oil recovery in field core tests was poor because of stringent capillary desaturation requirements.

Study to improve an amphoteric sulfonate alkyl ester surfactant by mixing with nonionic surfactant to reduce brine–waxy oil interfacial tension and to increase oil recovery in sandstone reservoir: T-KS field, Indonesia

“…The formulation is conducted by mixing amphoteric SAE with nonionic (ester group) surfactants. This differentiates with previous authors who mixed anionic with nonionic surfactants (Kremesec et al 1988;Martiz et al 2015) or anionic with cationic surfactants (Li et al 2016).…”

“…Nonetheless, study by Martiz used pure alkane and the interfacial tension was above 10 mN/m, while most enhanced oil recovery purposes require interfacial tension of oil-water below 10 − 2 mN/m. Kremesec et al (1988) studied mixtures of anionic crude oil sulfonate and nonionic ethoxylated alcohol surfactants and they observed through laboratory experiments that low IFT and good solubilization parameter could be achieved by optimizing the HLB of nonionic surfactant. Marhaendrajana et al (2017) showed that sulfonated alkyl ester (SAE) surfactant reduces the interfacial tensions of both heavy and light oil samples with water in a wide range of salinity with monovalent and divalent ions present.…”