Numerical Analysis of Corrosion Rate Induced by Slugging in a Pipeline

Abstract Pipeline slugging pose significant risks to the integrity and longevity of oil and gas pipelines. This study investigates the impact of slugging in pipeline on corrosion, ascertaining the corrosion rate for three different models (NOSOK Model, IFE Top-Of-Line Corrosion Model and de Waard 95 models) and the slug liquid volume, accumulated liquid volume, outlet pressure and riser base pressure of the system. OLGA simulator was used to develop the pipeline-riser model, and multiflash used as a phase behavior modeling tool. The generated PVT table file in multiflash was imported into OLGA, creating a base case pipeline-riser and flowpath together with the nodes to represent the inlet and outlet of the pipeline and a bypass line inserted as an auxiliary line that connects the Subsea-Tieback with the main riser to lift the flow at a certain point above the riser base. The model was validated and run for 2 hours to evaluate the susceptibility of the system to slugging and corrosion. Result shows increase in corrosion rate from stratified flow to slug flow for NOSOK Model and IFE Top-of-line model while de Waard 95 models did not show any rate of corrosion in the system. NOSOK Model has the highest corrosion rate for both stratified and slug flow in the pipeline. There was an increase in the surge liquid volume, accumulated liquid volume, outlet and riser base pressure for flow changes from stratified to slug. This study reveals that pipeline slugging substantially increases corrosion rates, particularly in liquid holdup regions, due to enhanced erosion-corrosion and elevated wall shear stress.