Interaction of Amphiphilic Polymers with Medium-Chain Fatty Alcohols to Enhance Rheological Performance and Mobility Control Ability

To improve the efficiency of mobility control for polymer flooding, a novel thickening system was formed by adding medium-chain fatty alcohols to hydrophobically modified polyacrylamide (HMPAM) brine solutions. The interaction of HMPAM with fatty alcohols was investigated in term of rheology properties, aggregate microstructure, and mobility control ability. The results show that n-octanol (C8OH) generates the best synergistic behavior with HMPAM compared to other fatty alcohols. More hydrophobic groups initially existing in either intramolecular or intermolecular association reassemble into larger aggregation structures due to the presence of C8OH. 750 mg•L-1 C8OH could lead to an increase of viscosity by 4 times as individual HMPAM at low polymer concentration (1000 mg•L-1). Owing to the enhancement of association structure, the HMPAM+C8OH system displays stronger shear-thinning behavior, higher viscoelasticity and better resistance to salt and temperature. Polymer-brine displacement tests indicate that...