In this paper,a series of experiments,including atomic force microscope (AFM),environmental scanning electron microscope (ESEM),and core displacement tests were conducted to investigate the effect of polymer solution structure on solution properties and oil displacement efficiency.The results show that in the HPAM solution polymer coils were formed and then aggregated into a loose structure,while the HAP2010 solution formed a strong network structure,which would significantly improve the solution viscosity and flow resistance so as to upgrade the capacity of piston-like oil displacement in highly permeable porous media.Meanwhile,the retention of the HAP2010 solution at pore throats were also enhanced,which could reduce water production during subsequent water flooding and enlarge the swept volume during polymer flooding.Therefore,enhancing the interaction among polymer molecules is an effective way to improve the displacement efficiency of polymer solutions in heavy oil reservoirs with high permeability.