New insights into wax deposition challenges: Experimental investigation across varied pipeline curvatures

Abstract

This study investigates the intricate phenomenon of wax deposition in oil pipelines, with a primary focus on enhancing the understanding of wax deposition mechanisms. Special attention is given to the role of pipe curvature in influencing these deposition processes, exploring how bends in pipeline structures may alter the behaviour of wax deposition, potentially leading to operational challenges. A novel flow rig was designed and commissioned to simulate wax deposition in straight pipes and pipes with 45° and 90° bends at both horizontal and inclined positions. The objective of the work is to quantify the impact of flow parameters, such as the temperature and flow rate, on wax buildup under different pipe configurations. The results demonstrate that the temperature and flow rate are critical factors influencing wax deposition processes. Specifically, lower temperatures (ranging from 10 °C to 30 °C) and laminar flow conditions (Re < 2000) significantly aggravate wax deposition. It was found that pipe curvature plays a crucial role in the severity of wax buildup. For instance, the pipes with 45° and 90° bends exhibited deposition rates up to 8 % and 10 % higher than those observed in straight pipes, under the same flow conditions. These findings highlight the importance of incorporating pipe curvature effects into wax deposition models, especially in pipelines with complex geometries. This study provides new insights into enhancing the accuracy of predictive models for wax deposition. It highlights the importance of incorporating additional mechanisms, such as Brownian diffusion and gravity settling, in conjunction with traditional factors like molecular diffusion and shear dispersion.