The Impact of Brine Salinity/Concentration on Small Amplitude Oscillatory Shear (SAOS) Flow Material Functions of EOR Polymers.

Abstract

Flopaams polymers are water-soluble polymers which display a significant degree of sensitivity to salinity changes as they consist of negative charges along their molecular chains. Electrostatic charges present along the backbone of a polymer molecule causes stretching (which results from repulsion of electrons) of the polymeric chains in water. The repulsion of these charges extends the molecular chain and gives it a rigid structure which results in high viscosities. When these polymers are exposed to a saline environment, the opposite charged cations present in salts makes the polymers loose their charges and the molecules loose their rigidity and become flexible. This drastically changes the physical properties of the solution of which a reduced polymer viscosity is easily noticed. Small Amplitude Oscillatory Shear (SAOS) material functions such as: Complex Viscosity Coefficients (alternatively, storage and loss moduli) were measured for four (4) Flopaam polymers. Sensitivity analysis were carried out to determine how these material functions depend on the polymer concentration and brine salinity. Comparisons were made with predictions made by an advanced non-Newtonian fluid model (C-FENE-P). Results show that the C-FENE-P dumbbell model is capable of understanding the effects of salinity in Small Amplitude Oscillatory Shear (SAOS) flow. At the same time, it should be extended to a more realistic Bead-Spring-Chain model variant in order to resolve the quantitative relations between SAOS flow material functions.