Effect of hydrophobic association on the flow resistance of polymer solutions

Comprehending the percolation law of polymer solutions in porous media is the basis of effective application of polymer flooding. The solution properties of partially hydrolyzed polyacrylamide (HPAM) and the hydrophobically associating polymer AP-P4 were compared, and the seepage characteristics in porous media were studied. The results showed that HPAM is a viscoelastic fluid dominated by a viscosity modulus. The smaller hydrodynamic size (≥3 µm) and low adsorption capacity (200 µg/g) caused an increase in the resistance factor of HPAM in porous media with the increase in injection velocity. Hydrophobic association greatly improved the solution properties of the polymer, with a stronger apparent viscosity, elastic modulus, hydrodynamic size (≥10 µm), and adsorption capacity (780 µg/g), showing that the viscoelastic fluid properties were dominated by the elastic modulus. The resistance factor of the polymer solution in porous media decreased with the increase in injection velocity.