Abstract
As-synthesized oleic amido propyl betaine surfactant mixture, that was produced through a “direct formulation through synthesis” process, exhibited ultra-low oil/water interfacial tension (IFT) values as low as 3.5 × 10−4 mN/m when dissolved in seawater at a reservoir temperature of 96 °C. The as-synthesized surfactant, which was left untreated, had a slightly cloudy appearance when mixed with seawater. Polar solvents were introduced to this surfactant to improve its aqueous solubility by changing its overall hydrophilicity, particularly on the oil/water interface. In this study, two types of glycol ether co-solvent, i.e., ethylene glycol monobutyl ether and diethylene glycol monobutyl ether, were used at different concentrations in a single application and as a mixture of co-solvents at a certain ratio. The behavior of the as-synthesized surfactant with the presence of these co-solvents was investigated. As a result, it showed that the co-solvent helps in solubility improvement and alters the interfacial tension behavior of the surfactant. Ethylene glycol monobutyl ether was found to be efficient in maintaining an ultra-low IFT value of the surfactant. However, the aqueous solubility of the surfactant was not significantly improved. In contrast, the addition of diethylene glycol monobutyl ether showed improvement of the aqueous solubility of the surfactant, but it tends to increase the IFT above ultra-low value. Based on this understanding, a set of co-solvent mixing ratios were tested, and the results showed further improvement in both the oil/water interfacial tension behavior and surfactant aqueous solubility. The most stable oil/water IFT of 3.36 × 10−3 mN/m and clearer surfactant solutions were obtained for ratio C at 35 wt.% presence of co-solvent.
Highlights
In the enhanced oil recovery (EOR) method, surfactant flooding is one of the most efficient ways to improve oil displacement from a depleted reservoir
The instability of the dynamic Interfacial tension (IFT) and slightly cloudy appearance of as-synthesized oleic amido propyl betaine surfactant mixture with a long hydrophobic tail can be improved by adding ethylene glycol mono butyl ether (EGME) and diethylene glycol mono butyl ether (DGME)
The appearance issue needs to be solved before it mixture at Figure 8 represents the as-synthesized surfactant in the presence of a co-solvent mixture in ratio B (3:1), in which the concentration has been varied from 0.05 to 0.5 wt.%
Summary
In the enhanced oil recovery (EOR) method, surfactant flooding is one of the most efficient ways to improve oil displacement from a depleted reservoir. Surfactant was added to the oil/water system, and the interfacial tension between the water and oil was reduced to a certain level that should be enough to displace the trapped oil. For greater performance of the chemical oil displacement system in EOR, its important index of interfacial tension (IFT) is preferred to be at an ultra-low level Extensive research has been done worldwide to search for the best surfactant for the said application [2,3,4]. Amphoteric surfactant is one of the surfactants that has been studied worldwide for applicability in EOR. In the study done by [6], it was found that amphoteric surfactant produced the most ultra-low IFT value out of 30 surfactants that were synthesized
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
