A New Correlation for Prediction of the Kinematic Viscosity of Crude Oil Fractions as a Function of Temperature, API Gravity, and 50% Boiling-Point Temperature

A new kinematic viscosity-temperature correlation for liquid petroleum fractions has been developed to represent the experimental data for a wide range of temperatures (100 to 400°F, 37.8 to 204.4°C). The only characterization properties required for estimation are the API gravity and the 50% boiling-point temperature (Tb). Fitting parameters have been evaluated for 156 experimental data points from 12 true boiling-point fractions of Arab heavy, Arab medium, and Arab Berri (extralight) crude oils with boiling ranges from 200 to 850°F (93.3 to 454.4°C) and also for 102 data points of 34 other world crude oil fractions. In addition, fitting parameters have also been evaluated for both Arabian and other world crude-oil fractions. The proposed correlation fits the kinematic viscosity data with an overall average relative error of 2.75% for the 12 Arabian crude-oil fractions and 4.46% for the 34 other world fractions. The fitting correlation when used for all available experimental data gives an overall average error of only 3.5%.