Experimental investigation of the behaviour of a novel amino acid-based surfactant relevant to EOR application

Abstract

Acylated amino acids, a group of amino acid-based surfactants have been the focus of recent studies as green alternatives to petrochemical-based surfactants yet their enhanced oil recovery (EOR) potential is understudied. The few reported amino acid-based surfactants in literature showed less satisfactory performance compared to conventional surfactants with regards to their EOR application. In this present study, however, sodium cocoyl alaninate (SCA); an amino acid-based surfactant has been proven to have excellent properties relevant to its EOR application. It proved to have comparable or even better performance to commonly deployed surfactants for EOR application. Its surface activity and thermodynamic properties of aggregation are evaluated. The aggregation behaviour was considered employing surface tensiometry and conductometry data. With EOR application in mind, the interfacial tension (IFT) and wettability modification studies were made as well. The results were compared to conventional surfactants and other amino acid-based surfactants. SCA has surface tension reduction efficiency and effectiveness of 2.74 and 40.79 mN/m respectively compared to sodium dodecyl sulfate (SDS) with 2.51 and 32.5 mN/m. This proves that SCA is superior to SDS in terms of surface activity. Furthermore, with 91% reduction in IFT by SCA compared to 89% reduction by SDS, the superior surface activity of SCA to SDS was confirmed. There was evidence of synergy in reducing IFT when salt was added. About 47% improvement in IFT reduction was observed. SCA also has a superior ability to SDS and CTAB in modifying quartz and carbonate surfaces' wettability respectively. Quartz surface was altered from intermediate wet to water wet while carbonate surface was altered from oil wet to water wet. SCA, therefore, proves to be an excellent alternative to conventional EOR surfactants due to its superb surface activity coupled with its environmentally benign nature.