The early polymer injection technology can further improve the polymer flooding effect

and the method to judge the time of polymer transfer by laboratory experiment and numerical simulation is relatively complex and limited in application. Based on the mechanism of oil-water relative permeability

an application method for quickly determining the time of injection and accumulation is established by using reservoir engineering method. The characteristics of the relative permeability curves of four reservoirs are obtained through laboratory experiments

and the influence of the water cut change rule

water cut rise rate

dimensionless production fluid（oil） index

oil-water mobility ratio and other characteristic parameters on the injection timing of polymer flooding under different reservoir conditions is analyzed by the reservoir engineering method. The results show that the above characteristic parameters are obviously different under different reservoir conditions. The injection time of polymer flooding should be determined by sorting the characteristic parameters according to the actual demand. Taking production as an example

the dimensionless production index

dimensionless production index

water cut rising rate and oil-water flow rate ratio determine that the water cut of the injection time for four reservoirs（BZ

JZ

QHD and SZ） is above 80 %

79.9 %

86 % and 34 %

respectively. According to the actual situation of the field

the time of polymer injection time can be determined quickly by analyzing the relative permeability curve with reservoir engineering method.