RETRACTED: Striking behavior of the rheology in heavy crude oils by adding nanoparticles

Abstract

The main objective of this paper is to provide unexpected experimental evidence of heavy oil and extra-heavy crude oils viscosity reduction resulting from the presence of nanoparticles of different chemical natures (SiO 2 , Fe 3 O 4 , and Al 2 O 3), surface acidity, and concentration at low-volume fractions. The viscosity of the enhanced fluids was measured using a rotational rheometer at shear rates varying between 1 and 75 s À1. Upon addition of nanoparticles viscosity reduction was observed in all cases evaluated. However, the maximum viscosity reduction of roughly 52% was obtained at a concentration of 1000 mg/l with 7 nm SiO 2 nanoparticles at low shear rate, below 10 s À1 , contrary to expectations from Einstein's viscosity theory in particulate systems. A mathematical model based on a modification to Pal and Rhodes Model for viscosity of suspensions is proposed in this work. The said model was validated successfully using experimental data, as evidenced by root-mean-square error values lower than 10%. The importance of our findings lies in the lack of prior experimental and theoretical data in the open literature showing heavy crude oils viscosity reduction in the presence of nanoparticles.