(672a) Modeling of Wax Deposition in Production Pipelines

Wax deposition in production pipelines is a topic of concern in the oil industry. Wax gets crystallized when the temperature of the crude oil containing paraffin wax drops below the wax appearance temperature (WAT). Crystals may then accumulate on the surface of the wall leading to reduced production rate and higher pressure drop. Managing this issue is expensive due to the downtime associated with treatment methods. Therefore, an accurate model to predict the rate of asphaltene deposition is needed to address this topic. Majority of existing models predict the deposition rate by using molecular diffusion.

In this study, a model is developed based on the size of wax particles: dissolved, precipitated, and aggregated. The concept of a critical particle size and sticking probability are also applied in this model. The growth of wax particles over time is simulated using a population balance model, and particles bigger than the critical size are assumed to not be able to deposit due to the advection force of the flow. Experimental data points are used to verify the model performance.