Perpustakaan Digital ITB

This research assesses the technical viability of Sulfonated di-Alkyl Ester (SAE-2), a polymeric surfactant, for chemical enhanced oil recovery (CEOR) in ultra-low salinity brine (300 ppm NaCl). Base formulation SAE-2 at 1.0 %wt reduced the interfacial tension (IFT) of high-wax crude oil from 3.386 mN/m to 0.913 mN/m. Systematic screening of alkaline agents, divalent cations, co-solvents, and co-surfactants was conducted to optimize performance. Sodium carbonate (Na?CO?) promoted in-situ soap generation and significantly lowered IFT but increased ionic sensitivity. While calcium ions (Ca²?) caused severe destabilization, magnesium ions (Mg²?) remained tolerable and contributed to IFT reduction. To overcome the stability-activity trade-off, 1.5%wt ethylene glycol butyl ether (EGBE) was incorporated as a cosolvent, maintaining clear aqueous stability for seven days at 60°C. The optimal formulation (19J) comprising 1.0 %wt SAE-2, 2.5 %wt Na?CO?, 100 ppm MgCl?, and 1.5%wt EGBE, achieved IFT of 0.04846 mN/m and formed a stable Winsor Type II microemulsion. Spontaneous imbibition tests on Berea cores yielded exceptional oil recovery of 95.61%, compared to only 50.55% for formulations containing nonylphenol ethoxylate (NPE). These findings demonstrate that Formulation 19J is highly technically feasible for reservoir-scale surfactant flooding in ultra-low salinity environments.