Keywords: Visco-elastic property; polymer flooding; oil recovery Abstract. Polymer flooding and ASP flooding has improved oil recovery a lot in Daqing oil field. In ASP flooding, the existence of alkali decreases the visco-elastic characteristic of polymer, which decreases the oil recovery of polymer flooding. The aim of this paper was to study the visco-elastic characteristic, shear resistance in high concentration and high molecular weight polymer flooding, and analyzed the suitable parameter of it .They can provide the theory of polymer flooding development and application research.

When the dose level of polymer is settled, the change of injection volume and concentration do not increase oil recovery obviously, while the result of lab research shows that the increasing of oil recovery of high concentration and high molecular weight polymer flooding can reach or over that of ASP flooding. The aim of this paper is to study the shear characteristic in high concentration and high molecular weight polymer flooding, and analyzed the suitable parameter of it.They can provide the theory of high concentration Polymer flooding. In the process of polymer flooding, it was because increasing the water phase viscosit and the retention effect of polymer molecules in porous media that making oil flow degrees than improved ,the sweep volume expand, and improve the oil recovery. Study confirmed [1-3], polymer solution with sticky elastic can effectively improve the oil displacement efficiency, reduce residual oil saturation [4-5]. So, the study on the shear properties of the polymer system in high concentration (>1000mg/L) can provide experimental base for a high concentration of polymer flooding, it also has important significance on theory of polymer flooding development and application research.