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 (T_b). 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%.