Research on viscoelasticity and its influence factors of polymer solution

The Wiesenberger number is a common dimensionless quantity to reflect the elastic effect of fluids. It's usually applied in mechanical calculation of viscoelastic fluid and calculated by the first normal stress difference. So the first normal stress difference and Wiesenberger number are applied to describe the viscoelasticity of polymer solutions. Though many literature reviews on the viscoelasticity of polymer solutions have been reported, only a few studied the Wiesenberger number and the first normal stress difference of viscoelastic fluid. Since the corresponding relation between Wiesenberger number and mass concentration and salinity of polymer solution is not clear, HAAKE RS 150 rheometer was used during all steady and dynamic shear experiments, effects of mass concentration and salinity on the visco-elasticity of polymer solution in low shear rate were discussed, first normal-stress difference and Wiesenberger number were calculated. Results show that: with the increase of mass concentration of polymer solution and the decrease of salinity, both first normal-stress difference and Wiesenberger number increase, the visco-elasticity of polymer solution increases; At the same shear rate, the higher the salinity is, the smaller the first normal stress difference is, the smaller the Wiesenberger number is and the less obvious the viscoelasticity is. The Wiesenberger number of ordinary polymer solution used in the oilfield is about 1 when the shear rate is 10s(-1) and salinity is 508mg/L.