Potential Oil Recovery Enhancement by a Polymeric Nanogel Combined with Surfactant for Sandstone Reservoirs

The aim of this study is to examine the effect of a novel combination that consists of polymeric nanogeland surfactant on oil recovery. The paper will report the extent to what the nanogel, alone and combinedwith surfactant, can improve oil recovery for sandstone reservoirs and reveal the mechanisms behind it. Anegatively charged nanogel was synthesized using a typical free radical suspension polymerization processby employing 2-acrylamido-2-methyl propane sulfonic acid monomer. In addition, a fixed concentration ofnegatively charged surfactant (sodium dodecyl sulfate or SDS) was combined with different concentrationsof the nanogel using seawater. The combination effect on sandstone core plugs was examined by runninga series of core flooding experiments using multiple flow schemes. The synthesized nanogels showed anarrow size distribution with one peak pointing to a predominant homogeneous droplet size. They were alsoable to adsorb at the oil-water interfaces to reduce interfacial tension and stabilize oil-in-water emulsions,which ultimately improved the recovered oil from hydrocarbon reservoirs. The results suggest the ability ofthe nanogel, both alone and combined with SDS, to improve the oil recovery by a factor of 15% after initialseawater flooding. Although nanoparticles have received a great attention in the research aspect of the oilindustry, however, the characterization of polymeric nanogels, alone and combined with other additives,is still to be investigated. Due to their unique properties and mechanisms, nanogels have a great potentialfor application in the oil industry. This study is aimed to examine and evaluate the combination of chargedpolymeric nanogel and surfactant dispersed in seawater through core flooding experiments using multipleinjection schemes