Aiming at the low production level of the oil layer caused by the reservoirs with low permeability and the large contradiction between oil layers

we commonly use different medium injection tools in the oil fields to realize the match of polymer injection and polymer molecular weight to the oil layer. In order to reflect the effect of shearing on viscosity of polymer solution when it across the interstitial injection tools

a mathematical model about the impact on polymer apparent viscosity affected by shearing was established

and the influence of the structural parameters of interstitial injection tools and injection volume on the apparent viscosity of polymer was analyzed. The results showed that the apparent viscosity of the polymer solution went up when the length of contractile section

radius of cylindrical section

maximum diameter of dilated section and length of dilated section increased

while the apparent viscosity of polymer solution went down when the radius of the contractile section increased. And the length of cylindrical section had no effect on the apparent viscosity of polymer solution. The apparent viscosity of polymer solution decreased when the injection volume of the polymer solution increased. The calculation results can provide a theoretical reference for optimizing the structural parameters of the different medium injection tool.