A general model for the viscosity of waxy oils

Abstract

A generalized viscosity model suitable for describing the non-Newtonian behaviour of waxy crudes has been developed. The model, which has the following expression predicts the viscosity as a function of shear rate, temperature, and wax concentration: μ= B 1 γ γ+A 1 A 1 n−1 (1/n) e (C/T+D×W) where μ is the viscosity, γ is the shear rate, T is the temperature, and W is the percentage of wax. The viscosity measurements were performed by measuring the rheological properties of the waxy oil at four different concentrations and five different temperatures. A reduced form of the model may be used to predict the viscosity of Newtonian and non-Newtonian fluids with or without yield stress. The proposed model was found to fit the experimental data well as demonstrated by a high coefficient of correlation (97.5%). The nonlinear regression analysis was used to determine the model parameters A, B, C, and n.