Hydrogel swelling properties: comparison between conventional and nanocomposite hydrogels for water shutoff treatment

Abstract One of the unique properties of hydrogels is the dramatically change in their volume and shape. In this research, conventional hydrogels (composed of sulfonated polyacrylamide and Cr(OAc) 3 as copolymer and crosslinker, respectively) were investigated versus nanocomposite (NC) hydrogels for the purpose of achieving suitable composition with ability of high amount of equilibrium swelling ratio and low amount of salt sensitivity factor ( f ). The results showed that high ratio of Cr(OAc) 3 /copolymer (>0.39) and high concentration of copolymer (>27 000 ppm) were suitable areas for conventional hydrogels because of minimum f factor with still low ability of gel swelling. However, the results of NC hydrogels with composition of copolymer concentrations of 23 750 to 30 000 ppm, Cr(OAc) 3 /copolymer ratio of 0.28 and nano Na‐MMT concentrations of 500 to 800 ppm represented a significantly high amount of swelling and low amount of f factor. Coreflooding tests were applied to investigate the effect of polymer gel swelling in porous media for water shutoff treatment. The values of the residual resistance factor of water/oil for samples with high and low swelling ratio were 32.34 and 7.08, respectively, confirming the ability of the polymer gel with high swelling ratio in reducing the relative permeability of water/oil in porous media. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd.