Numerical Estimation of Wax Deposition Rates in a Niger Delta Pipeline: Implications for Pigging Frequency

Abstract

Wax buildup in Niger Delta crude oil pipelines is a major challenge that often leads to expensive blockages. This study looked at a 19.4 km pipeline in the region to demonstrate how simulation tools can take the guesswork out of planning pigging schedules. Analysis in Multiflash showed that the crude has a Wax Appearance Temperature (WAT) of 48 °C and a wax content of 1.2%. Steady state simulations with PIPESIM revealed a critical detail. While pressure remains stable, the oil cools below the WAT just 0.5 km from the inlet. This means wax settles along nearly the entire length of the pipe. By using OLGA software for dynamic simulations, it became clear that about 75 kg of wax accumulates every month, when operated at 0.63 kg/s and 60 °C, making a 30-day pigging cycle the most effective choice for this pipeline. The study also demonstrated that a pig speed of 0.12 m/s is ideal, resulting in a 40-hour travel time. Ultimately, combining these simulation tools provides a reliable way to predict wax behavior and keep pipeline operations running safely and efficiently.