Evaluation of functionalized polymeric surfactants for EOR applications in the Illinois Basin

Molecular modification of water-soluble hydrolyzed polyacrylamide (HPAM) with surfactant-like monomers, known as the functionalized polymeric surfactant (FPS), can be an effective enhanced oil recovery (EOR) method. The FPS-EOR operation is very similar to the conventional polymer flooding (P-Flooding), in terms of the chemical use and field injection costs, but with a potential to further recover more than 5% of OOIP compared to the HPAM-EOR alone. Laboratory tests and a third party core-flood result show FPS can recover more oil than HPAM even at the lower injection pressure. Surfactant-like monomers linked to the FPS backbone improve the microscopic displacement efficiency of water-soluble polymer by pulling them towards the oil-water interface and creating an oil-water emulsion. Unlike the conventional surfactant +polymer (S+P) multi-component systems, single-component FPS-EOR injection has both the sweep efficiency (polymer feature) and the microscopic displacement efficiency (surfactant feature), but can mitigate incompatibility issues such as chromatography separation and surfactant-polymer interactions. Unlike a typical surfactant flooding for which the reduction of oil-water interfacial tension (IFT) to an ultralow level (< 10(-3) dyne/cm) is required, a typical FPS solution only reduces IFT to a moderate level (similar to 10(-1) dyne/cm) at the polymer concentrations of 1000-3000 ppm. (C) 2015 Published by Elsevier B.V.