Evaluation of empirically derived oil viscosity correlations for the Niger Delta crude

This paper presents the evaluation of oil viscosity correlations for the Niger Delta crude. The viscosity properties considered are: dead oil viscosity, viscosity at the bubblepoint and the undersaturated oil viscosity. The existing oil viscosity correlations were assessed for their performances using viscosity database from the Region. Both quantitative and qualitative analytical methods were implemented using statistical parameters and performance plots respectively. From the general evaluation, using percent mean absolute relative error (Ea) as the screening criterion. It has been shown that Beal (1946) correlation is the best for undersaturated oil viscosity with Ea of 6.7291, Beggs and Robinson (1975) is the best for bubblepoint oil viscosity with Ea of 24.4274, while Labedi (1982) is the best for dead oil viscosity with Ea of 31.2628.