Morphology of polyacrylamide in solution: effect of water quality on viscosity

When used in polymer flooding for enhanced oil recovery, polyacrylamide (PAM) is an effective viscosifying agent and has been widely used for polymer flooding in oilfields in China for many years. Practical experience has shown that the use of oilfield treated produced water instead of fresh water, driven by economic and environmental considerations, leads to reduced viscosity of PAM solutions and hence poorer performance. To better understand the causes of viscosity degradation and to be able to control it, the morphology of polymer in different water quality conditions was investigated to reveal the relationship between the morphology and viscosity of PAM solutions. The effect of water quality on viscosity of PAM solution was also analyzed. The results show that the morphology of PAM solution prepared with deionized water exhibited a uniform three-dimensional network structure. Both divalent metal ions and suspended substances have significant effects on PAM morphology and viscosity, but the effect of suspended substances is larger than that of divalent metal ions. Copyright (c) 2015 John Wiley & Sons, Ltd.