Thermal removal mechanism of paraffin deposits: Impact of flowrate on removal efficiency

Abstract

Active heating is increasingly explored as a cost-effective strategy for managing wax deposition in production flowlines. While these methods are commonplace throughout the industry to maintain or raise the temperature of the production fluid above the wax appearance temperature (WAT), there are no clear guidelines for wax removal using active heating. In this study, a novel dynamic microscopic visualization technique is used to observe the effects of the flow regime on the removal process. At high enough temperatures, 50.6 °C and 43.3 °C, 100% removal is observed in both turbulent and laminar cases. A removal temperature of 37.0 °C resulted in 72.5% removal under turbulent conditions, and 97% removal under laminar conditions. No reduction in thickness was observed in either case when removing at a temperature of 30.6 °C. Turbulent conditions were also shown to significantly increase the heating time required before detachment compared to laminar conditions at the same removal temperature. The turbulent experiments required 2.7 times as long for detachment to occur when removal temperatures were raised to 43.3 °C, and 4.6 times as long when temperatures were raised to 37.0 °C. Turbulent conditions are also shown to require higher temperatures to trigger the removal process, likely due to the harder deposits formed at higher flow rates. This analysis sheds light on the impact flow regime and deposit properties have on the removal process. The results obtained in this study enhance the understanding of the impact of flow on thermal removal and this knowledge is necessary for accurate removal modeling.