Pipe Insertion Technique for Slug Attenuation in a Downwardly Inclined Pipeline

Abstract

Slug flow is more prevalent in downwardly inclined pipelines and it is important to develop effective and suitable mitigation strategies to reduce its occurrence and enhance stable flow. In this work, the application of pipeline insertion was proposed to reduce slugging in pipeline. A simulation based approach was adopted and a model with smaller pipe sizes of 3.958-inch, 1.995-inch and 6-inch diameter, inserted near the pipeline riser system. The developed model was run for 2 hours to monitor the harsh nature of the slug on the total liquid volume flow, the pressure at the pipeline riser outlet, surge liquid volume and accumulated liquid volume. The result shows a stable liquid production of approximately 3797.08bbl/day and 3798.44bbl/day for the 3.958-inch and 1.995-inch diameter pipe size, while the total liquid flow oscillated between 7366.45bbl/day and 1.917.37bbl/day, and repeated at 0.22 hours. There was a pressure buildup and later steady at 761.978 psia and 762.127 psia for the 3.958-inch and 1.995-inch diameter pipe at the riser base while the 6-inch diameter pipe was fluctuating. Smaller diameter pipe of 3.958-inch and 1.995-inch gave a stable fluid pressure of 725.196 psia at the riser top (outlet) .Therefore, smaller diameter pipe is the best to insert since there was no cyclic fluctuation of pressure at the riser top, which can lead to severe slugging.