Thermo-rheological model predicts waxy crude oil behavior

SEP 04, 2026

The results should be valuable to the oil industry, where determining flow assurance conditions is a major problem.

Thermo-rheological model predicts waxy crude oil behavior internal name — Thermo-rheological model predicts waxy crude oil behavior lead image

Waxy crude oils (WCOs), made of high molecular weight hydrocarbons dissolved in oil at high temperatures, are commonly extracted from depths as low as 2,000 meters below sea level. After the flow in pipelines transporting them has been shut down for maintenance or emergency, getting the flow started again requires higher pressure gradients to unlock polymer chains that have gelled in the prevailing colder temperatures. However, knowing just what pressure to apply is a tricky question.

Mousavi et al. present the first complete thermo-rheological model predicting the behavior of a wide range of WCOs. With 16 flow-related and six temperature-related parameters, the model can predict properties including elasticity, plasticity, and thixotropy for a wide range of shear rates and temperatures.

The authors determined the model parameters for four different crude oils under a variety of specifically designed rheological tests. Analyzing the data with in-house software, they reproduced the experiments and determined the parameter values needed to describe oil flow. The resulting model applies in a broad temperature range, simplifying simulations and their interpretation.

“The advantage of our model is its applicability to a wide variety of WCO samples from different regions worldwide,” said author John Tsamopoulos. “Our model performs consistently well across these diverse datasets, an aspect that was not addressed in previous efforts.”

The authors have already applied their model to examine flow restart conditions and plan to develop a more generalized framework capable of incorporating dissipation at low strain rates, enabling accurate prediction of both solid-like and liquid-like behavior in different WCOs.

Source: “Constitutive modeling of waxy crude oils accounting for their shear and temperature history,” by Milad Mousavi, Alexandros Spyridakis, Yannis Dimakopoulos, and John Tsamopoulos, Journal of Rheology (2026). The article can be accessed at https://doi.org/10.1122/8.0001206 .