Experimental investigation of the effect of a quinoa-derived saponin-based green natural surfactant on enhanced oil recovery
School of Engineering / Centre for Sustainable Energy and Resources
In this study, a unique surfactant extracted from a quinoa plant was introduced for enhanced oil recovery (EOR). The physico-chemical characteristics of extracted saponin as the surfactant agent were confirmed by 1H NMR, FESEM, and FT-IR analyses. The natural surfactant extracted from quinoa exhibited appropriate thermal stability at reservoir temperature, even at very high temperatures, according to TGA test. Then, the efficiency of the quinoa-derived surfactant was compared against two common commercial surfactants, TR-880 and NX-610. Interfacial tension (IFT) and contact angle tests were performed, and the obtained results show that the novel surfactant, at its critical micelle concentration (CMC), contributes to an additional 24.1% of the original oil in place (OOIP) due to a significant reduction in contact angle from 146° to 26.3°, and a substantial reduction in IFT from 33.2 to 8.7 mN/m. Moreover, at the CMC point, contact angles of 72° and 58.8° were obtained for TR-880 and NX-610, respectively, which were higher than the natural surfactant value, although NX-610 and TR-880 surfactants both resulted in lower IFT values of 4.9, and 3.4 mN/m, respectively. Contact angle and zeta potential measurement confirmed that all three tested surfactants could change the wettability of the reservoir rock from oil-wetting to water-wetting, with natural surfactant achieving the most promising results in both tests. Emulsion tests showed that the quinoa surfactant produced more stable and denser emulsions compared to commercial surfactants. Therefore, this study introduces a novel surfactant that not only is cost effective and environmentally friendly, but also performs promisingly for EOR purposes.