Rheological study under simple shear of six gelled waxy crude oils

Rheological behaviour of gelled waxy crude oils is critical to designing subsea architecture for petroleum fields. The ability to generate dimensionless models to predict the rheological behaviour of any gelled waxy crudes would be a powerful tool. Validation of the model with experimental data from a wide range of gelled waxy crudes is an essential step to reach that goal. This study presents a rheological study of six commercial gelled waxy crude oils at a temperature of 5 °C. Four experimental procedures were performed in a controlled-stress rheometer MARS III from HAAKE GmbH with a cone and plate geometry. The rheological curves are steady state, stress sweep curve, constant shear rate and constant shear stress. We also did a study of the aging time with two of those oils. The strength of the crystalline structure of the six gelled waxy crudes have considerable difference, where the apparent yield stress ranges from 1 to 1000 Pa. The main challenges are to predict the overshoot of the stress in constant shear rate experiments and to predict the shear rate behaviour in constant shear stress experiments. Good accuracy was obtained from comparison of the model with the experimental data.