Irreversible time dependence of gelled waxy crude oils: Flow experiments and modeling

We introduce a constitutive model to describe the rheological behavior of gelled waxy crude oil. The irreversible time-dependence effects were experimentally characterized and incorporated into the model. The model is developed with basis on the data of standard rheological tests to determine the parameters of novel material functions that arise in the model development procedure, namely, flow curve, destruction, and construction tests. The fluidity is directly employed as the indicator of the structuring level of the material. Good agreement is observed between the model predictions and the data, corroborating its potential as a useful tool in the study of start-up flows of gelled crudes in pipelines. (c) 2020 The Society of Rheology.