Abstract: Polymer flooding has been carried out on large scale in Shengli oilfield, and the watercut declines remarkably,but the response characteristics vary in different parts. Influence of fluid viscosity, injection and production condition, injection timing and reservoir property on polymer flooding is studied on the basis of laboratory modeling, numerical simulation and pilot test in oilfield. The results show that:(1) The higher ratio of polymer solution to oil viscosity in situ, the higher efficiency of the polymer flooding, the more the polymer injected, the higher the recovery rate increased, the earlier production well conversion,
the higher the polymer flooding efficiency in middle/high watercut period. (2) The facies belts which are favorable to polymer flooding are channel marginal facies, channel fill facies,channel bar and flood plain facies in turn. (3) The positive rhythm is suitable to polymer flooding and the negative is not.
Besides, large channel reservoir should be avoided when poly merflooding areas are selected.

Key words: reservoir property, polymer flooding, remaining oil saturation, fluid viscosity