Assessing the effect of corrosion inhibitor on erosion–corrosion of API-5L-X65 in multi-phase jet impingement conditions

Erosion–corrosion of pipeline steel API-5L-X65 has in recent years become an important issue due to the high sand production rate and watercut in the maturing assets. The scope of using corrosion inhibitor to mitigate erosion–corrosion arises due to a number of industrial demands. The present study has been conducted to assess the performance of API-5L-X65 and the effect of corrosion inhibitor under high velocity (20 m s−1) jet impingement in four types of media containing 1.5 wt% sand particles: synthetic Forties brine, Forties brine with 5 vol% hydrocarbon (ISOPAR M), Forties brine and 100 ppm corrosion inhibitor, and Forties brine containing 5% ISOPAR M and 100 ppm corrosion inhibitor. Under jet impingement, the material loss was determined by gravimetric measurements and it is shown that the presence of corrosion inhibitor or hydrocarbon reduces the total material degradation of the pipeline steel in Forties brine. The most significant reduction in material loss rate for pipeline steel appears to result from the media containing both hydrocarbon and corrosion inhibitor in this study where an extremely strong interaction is observed. In situ electrochemistry combined with surface analysis and CFD simulations of the jet impingement have enabled the degradation mechanisms to be studied for different erosion–corrosion conditions.