Perpustakaan Digital ITB

Implementing Chemical Enhanced Oil Recovery (CEOR) via alkaline-surfactant flooding requires understanding how brine ionic composition affects surfactant behavior. This study evaluated the effects of multicomponent ionic systems on microemulsion formation, phase behavior, and interfacial tension (IFT) reduction to develop an optimum formulation for oil recovery. The performance of Linear Alkylbenzene Sulfonate and Alpha Olefin Sulfonate (LAS:AOS 50:50) and Sulfonated di-Alkyl Ester (SAE-2) was evaluated through IFT measurements, aqueous stability, phase behavior, and spontaneous imbibition tests at 65°C. Results indicated that monovalent cations increased IFT relative to base brine, whereas 200 ppm Mg²? achieved the lowest screening IFT of 0.082 mN/m. Conversely, carbonate ions significantly increased IFT, particularly when combined with divalent cations, reaching 0.225 mN/m. All screening formulations exhibited Winsor Type II phase behavior. Formulation optimization revealed that surfactant selection and salinity were critical for achieving ultra-low IFT. The optimum formulation comprising 0.75 wt% SAE-2, 1.5 wt% Na?CO?, 20,000 ppm NaCl, and 2 wt% Ethylene Glycol Monobutyl Ether successfully achieved an ultra-low IFT of 0.00804 mN/m. In spontaneous imbibition tests, this SAE-2 formulation yielded an oil recovery factor of 44.74%, significantly outperforming the optimized LAS:AOS formulation (13.17%) and base brine (4.13%), demonstrating its superior potential for CEOR applications.