Rheology and polymer flooding characteristics of partially hydrolyzed polyacrylamide for enhanced heavy oil recovery

Abstract Polymer flooding characteristics of partially hydrolyzed polyacrylamide (HPAM) solution with the addition of NaOH were examined in homogeneous glass‐bead packs. The heavy oil recovery in unconsolidated sandstone formations by applying the alkali‐polymer flooding was observed. Experimental results showed that HPAM solution was sensitive to temperature, salinity, and alkali, finding that alkali‐polymer solutions are more effective in improving viscosity than conventional polymer solutions. The solution of 0.5 wt % NaOH mixed with 1500 ppm HPAM (12 mol % hydrolysis degree) was found to be the optimal choice, which gives rise to the highest viscosity on the rheological characterization. Flood tests using the alkali‐polymer solution showed an increase in oil recovery by 30% over water‐flooding when the water‐cut reached 95%, indicating that alkali‐polymer could be more effective in improving sweep efficiency than polymer flood. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013