Prediction of Waxy Oil Rheology by a New Model

The formation of wax particles influences the rheological behavior of crude oils. Different studies show that crude oils have a Newtonian behavior above the wax appearance temperature (WAT) and shear thinning non-Newtonian behavior below it. In this work, a model based on a combination of the Richardson and Herschel-Bulkley models, together with the simplified Eyring equation, has been presented. The parameters of the model have been obtained as a function of wax content (precipitated wax as a function of temperature), API, and temperature, which is a priority for the new model. To validate the model, some experimental data related to North Sea oils has been applied. The experimental data points utilized to calculate model parameters (162) show an average absolute deviation (AAD%) of 18.45% from the experimental data. Also, to show the reliability of the new model, it has been evaluated by another experimental data including 118 data points related to kinematic and apparent viscosity of 14 oils. Totally, the new model has an AAD% of 19.47% for the 280 experimental data points applied in this work. Also, the new model can predict the trend of viscosity variation against temperature, shear rate, and wax content, in comparison with the experimental data.