High molecular weight and water-soluble synthetic organic polymers are currently being used in the field with the hope of enhancing the recovery of oil by water flooding. Nanotechnology has been used in many applications and new possibilities are discovered constantly. Recently, a renewed interest arises in the application of nanotechnology for the upstream petroleum industry. The author focuses on roles of clay nanoparticles on polymer viscosity. Polymer-flooding schemes for recovering residual oil have been in general less than satisfactory due to loss of chemical components by adsorption on reservoir rocks, precipitation, and resultant changes in rheological properties. Rheological properties changes are mainly determined by the chemical structure and mix of the polymers, surface properties of the rock, composition of the oil and reservoir fluids, nature of the added polymers, and solution conditions such as salinity and temperature. On the other hand, the author's focus is on viscosity, temperature, and salinity of solutions polyacrylamide polymer solutions with different nanoparticles. Results show that ultimate oil recovery by nanoclay polymer flooding enhances by a factor of 5.8% in comparison to polymer flooding high salinity and temperature.