An experimental study was conducted to examine the effects of various alkalis, surfactants and brines on the viscosity of dilute aqueous solutions of Alcoflood 1175L, a partially hydrolyzed polyacrylamide polymer, over a wide range of parameters.

In general, the viscosity-shear rate relationship exhibited a Newtonian behavior at low shear rates and a power-law behavior at high shear rates. Adding a non-ionic species (Triton X-100) had an insignificant effect on the viscosity-shear rate relationship. However, adding an ionic species, (sodium chloride, calcium chloride, or an anionic surfactant) reduced the hydrodynamic size of the polymer molecule (physical change), changing the viscosity-shear rate relationship. The viscosity-shear rate relationship was found to be a strong function of cation type only at salt concentrations less than 4 wt%. For a given polymer concentration, the power-law constants were found to be exponentially related.

The effect of alkalis on the viscosity of polymer solutions was complex as they affected the polymer chain both physically (charge shielding) and chemically (hydrolysis). For alkali/polymer solutions, the viscosity was found to be a function of alkali type, concentration and time after initial mixing. The effect of these parameters on the viscosity of alkali/polymer solutions diminished by adding NaCl. The addition of anionic surfactants at low concentrations slightly decreased alkali/polymer solutions viscosity. However, a significant viscosity enhancement for alkali/polymer solutions was observed at higher surfactant concentrations and over a narrow range of alkali concentrations.

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