Role of silica Nano particles in altering rheological properties of drilling fluid in Enhanced Oil Recovery

Numerous methods have been adopted to alter the interfacial tension during the enhanced oil recovery (EOR) system. Much emphasis was given to the conventional methods of EOR because of its ease in operation and understanding. Efforts were made to use surfactants along with Nano particles as they could modify the rheological properties to a great extent with their complexion in the structure and properties. The combination of a cationic polymer (polyacrylamide) (PAM) in the presence of anionic surfactant (sodium dodecyl sulfate) (SDS) with varied concentrations of anionic Nano particle (silicon dioxide) in their complex aqueous solution form is investigated. At a known concentration of polymer and surfactant, the changes in rheological properties of fluid are studied for varied concentrations of silica Nanoparticles. Hydrated and un-hydrated polyacrylamide solutions were subjected to analysis at the well resembling temperature of 90OC, to know the effect of thermal stability of the polymer. It is observed that the fluid viscosity is reduced by two orders of magnitude with the addition of Nano particles, at low shears. However, the fluid showed shear thickening properties due to the complex structure among the polymer, surfactant and particle. The ionic charges interplay leading to the formation of complex structures at the hydrated state of polymer affects the viscosity of the fluid to a great extent.