Slow-release of surfactant from a hybrid polymeric hydrogel at high temperature

Surfactants are widely used in enhanced oil and gas recovery. Surfactants are usually injected into wells and reservoirs that are released in full upon the addition, and effectiveness lasts very short. Slow-release surfactant is preferred to be effective at an extended period. In this study, surfactant was encapsulated into the crosslinked hybrid hydrogel of polyvinyl alcohol (PVA) and poly acrylamide-2-methyl propane sulfonic acid (PAMPS). The encapsulated surfactant was slow-released at high temperatures. Free radical polymerization was used to polymerize acrylamide-2-methyl propane sulfonic acid and crosslink PVA in the presence of surfactant. The hybrid hydrogel complex was characterized by an infrared spectrum, electronic scanning microscope, and thermogravimetric analysis. The release profile of surfactant was studied in synthetic brine at 130°C. The results indicate that hybrid hydrogel encapsulated surfactant is stable and releases surfactant at high temperatures for more than 7 days. The diffusion of surfactant from hydrogel follows the zero-order kinetic model.