Effects of salt, and silica nanoparticles on rheological behavior of polyacrylamide solutions used in chemical enhanced oil recovery

In recent years, much attention has been focused on the use of polymer flooding as one of the enhanced oil recovery (EOR) methods [1]. The occurrence of high shear rates in reservoir and near well bore through polymer flooding cause shear degradation of polymers and therefore a decrease in polymer viscosity. Rheological behavior of polymer solution in different conditions of oil reservoir is one of the key factors to develop the use of polymer solutions. Recently, nanoparticles have attracted much attention due to their unique properties. Rheological studies showed that the viscosity of PAM increases by adding SiO2 NP. The interactions SiO2-PAM was evaluated through FT-IR spectroscopy. The role of nanoparticles in modification of the polymer performance in the presence of NaCl salt was investigated. The effect of concentrations on the viscosity of solution was investigated by adding silica nanoparticles to polyacrylamide at different NaCl salt concentrations. The results of viscosity measurements showed that increasing SiO2 nanoparticles concentration increases the viscosity of polyacrylamide solution and the influences of NaCl salt on the effective viscosity of PAM and PAM/SiO2 hybrids were examined at 25 o C, The viscosity was found to significantly increase at low salt concentrations, reaching a peak value, and then start to decline.[2,3]