Abstract: The macro - Theological data (i.e. apparent viscosities vs. shear rates) were measured by using a Haake rheometer for HP AM polymer solutions. Two rheological models (Power-Law and Cross) were well matched with the data measured. Effects of molecular weight, concentration, temperature and pressure on the macro - rheological characterization of polymer solutions were also analysed in order to provide basis of numerical simulation and performance prediction as well as engineering design for a pilot test.