With over 185,000 miles in the U.S. alone, petroleum pipelines are generally the most economical way to transport large quantities of crude and refined oil over land. However, paraffin (wax) that is naturally dissolved in crude oil at well temperatures, crystallizes and deposits onto cold pipeline inner walls. This is an issue especially with deep water wells due to very low ocean floor temperatures and extreme fluctuations in atmospheric pressure. Drilling, melting, and chemical dissolution are expensive cleaning procedures that are labor intensive and can damage the pipeline. Paraffin-crystal modifiers and dispersants are more cost effective approaches that prevent and inhibit wax deposition, but optimizing their use requires complex predictive modeling. Current methodology fails to account for the interaction between deposited microstructures and macro-scale fluid flow, resulting in imprecise models that require extensive additional tuning with experimental data.
Researchers at ASU have developed a multiscale procedure for modeling wax deposition using numerical simulations that integrate microstructure growth with the flow of the bulk liquid at the macro scale. This is accomplished by tracking the subjective motion and growth of many small particles and then reconstructing them within an objective schema once the wax structures reach a threshold size. Not only does this procedure model radial, molecular, and thermal diffusion of previously existing methods, it incorporates axial diffusion, flow rate, particulate dispersion, and turbulent flow into its calculations. Modeling microstructure growth also provides accurate information on the density and the aging process of the wax. This procedure realistically reflects the physical phenomena occurring between multiple scales in wax deposition, and is essential for the optimal design and implementation of various wax prevention techniques.
- Crude Oil Pipelines
- Deep Water Oil Wells
- Wax Deposition Modeling
Benefits and Advantages
- Accuracy – Multiscale modeling generates more precise predictions.
- Comprehension – Incorporates axial diffusion, flow rate, particulate dispersion, microstructure growth, and turbulent flow into its calculations.
- Innovation – Quantitative analysis of microstructure growth provides clearer insight into wax deposition and aging.
- Lower Costs – Better predictions result in less money spent on cleaning and prevention procedures.
For more information about the inventor(s) and their research, please see