Polymer viscosity versus polymer concentration (Dong et al., 2008) The polymer viscosity increases when the polymer concentration increases, as shown in Figure p27.įigure p27. The polymer concentration has a direct relationship with the polymer viscosity. Polymer viscosity versus temperature (Nouri & Root, 1971) However, this relationship does not always follow the same pattern it depends on other factors, such as the polymer concentration, molecular weight, salt, and hydrolyzation (Nouri & Root, 1971).įigure p26. In general, the viscosity of a polymer solution decreases as the temperature increases, as shown in Figure p26. Polymer viscosity as a function of salinity (Dong et al., 2008) The viscosity of the polymer is dominated by Ca 2+ in brine.įigure p25. Divalent ions can more effectively neutralize charges than monovalent ions, such as Na + and K +. Figure p25 illustrates the polymer viscosity reduction when the salinity increases.
The repulsive forces are shielded by a double layer of electrolytes when salt is added to a polymer solution. As the salinity increases, the distance between the polymer chain and the molecules decreases. Polymer viscosity is affected by water salinity and divalent ions such as calcium (Ca 2+) and magnesium (Mg 2+), which decrease the viscosity of the polymer solution. Polymer viscosity is affected by a number of factors, such as the salinity, temperature, concentration, molecular weight, and shear rate. Where q is the flow rate, A is the cross-sectional area, L is the length of the sample, ∆P is the pressure drop, and µ is the Newtonian viscosity of the flowing fluid.Polymer is a non-Newtonian fluid the apparent viscosity (𝜂app) is not a constant.The apparent viscosity can be defined by rearranging the above Equation as follows: Darcy‘s law describes the flow of fluid through porous media as The polymer viscosity is a key parameter in improving the mobility ratio.
The rheology of a polymer depends on many parameters, including the polymer type, molecular weight, polymer concentration, salinity effect, reservoir temperature, and shear rate. Polymer behavior is complex, and many laboratory studies have noted the occurrence of shear behaviors through porous media. The most important property of polymers is their viscosity, which significantly affects their behavior in porous media. The polymers most commonly used as mobility control agents include synthetic polymers (e.g., hydrolyzed polyacrylamide), biopolymers (e.g., xanthan), and, recently, associative polymer. Adding a small concentration of polymer to water will significantly increase the viscosity of the water (Nouri & Root, 1971). The polymer flooding method is used to improve the mobility ratio between oil and water.
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