Stability, flocculation, and rheological behavior of silica suspension-augmented polyacrylamide and the possibility to improve polymer flooding functionality

Abstract

In this study, the characterization and rheological behavior of silica suspensions in aqueous/polymeric media are investigated. The variation of silica nanoparticles size and concentration, polymer molecular weight and concentration, pH, valency, and concentration of electrolytes are considered for this purpose. The findings show that bridging flocculation of dispersed silica nanoparticle-augmented polymer solution increases with nanoparticle concentration, nanoparticle diameter, the charge of electrolyte, and electrolyte concentration. In contrast, it decreases with an increase in pH and polymer concentration. Also, the intrinsic shear viscosity of aqueous polymer solution increases with molecular weight, unlike the behavior of polymer solution in the presence of silica nanoparticles. The shear viscosity and the rate of bridging flocculation of the silica nanoparticle-augmented polymer solution primarily increase until it reaches a maximum and finally decreases with further increasing polymer molecular weight. In polymer high molecular weight and high concentration, the repulsion due to steric stabilization overcomes the interaction between two adsorbed polymer chains resulting in a stable form of suspension. By utilizing the proper conditions, core flooding experiments are designed and implemented to enhance the hydrolyzed polyacrylamide polymer flooding efficiency. Around 20–52% higher recovery was obtained for the silica nanoparticle-augmented polymer solutions with respect to the polymer flooding.