Polystyrene nanoparticles as surfactant carriers for enhanced oil recovery

It is well known that oil recovery processes can be increased by surfactant solution injections in the reservoir. However, the high adsorption of this type of compounds on the reservoirs rocks surface is one of the factors that have been preventing the Enhanced Oil Recovery (EOR) development and the economicity of the process. This work presents the synthesis of cross-linked polystyrene nanoparticles (PSNP) and their evaluation as surfactant carriers, able to percolate through the reservoirs pores and to deliver it at the water/oil interface. The nanoparticles were synthesized by emulsion polymerization of styrene and divinylbenzene in the presence of nonylphenol ethoxylate-10 (NF-10EO) or sodium dodecyl sulphate. Photon Correlation Spectroscopy and Interfacial Tension results gave support to the initial supposition that the nanoparticles would swell when in contact with the oil phase, releasing the surfactant at the interface. The nanoparticles obtained with NF-10EO were able to reduce the water/oil interfacial tension to values that were similar to the ones obtained with the aqueous solution of NF-10EO. The results suggest that the PSNP have a great potential to be used as surfactant carriers in EOR. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43789.