Criticality of Corrosion Inhibitor Selection in the Presence of LDHI for MEG Regeneration Elimination

Abstract In offshore oil and gas production, hydrate control has traditionally depended on continuous monoethylene glycol (MEG) injection, followed by energy-intensive onshore regeneration. To reduce operational costs and environmental impact, low-dose hydrate inhibitors (LDHIs) are being considered as alternatives. This study examines the corrosion inhibitor performance and compatibility of selected corrosion inhibitors (CIs) in the presence of LDHI under simulated pipeline flow conditions representative of CO2-rich multiphase environments. Testing was conducted using a high-pressure rotating cylinder electrode (HPRCE) using field parameters for temperature, salinity, acid gas partial pressure and shear stress. General corrosion was monitored via linear polarization resistance (LPR), while localized corrosion was evaluated post-exposure using white light interferometry (WLI). Results showed that complete removal of MEG in favor of LDHI can impair localized corrosion control for some corrosion inhibitors, despite general corrosion rates remaining within acceptable limits. However, co-injection of LDHI with a compatible CI achieved excellent inhibition of both general and localized corrosion, highlighting a synergistic effect. These findings highlight the importance of CI performance testing and compatibility against LDHI when modifying hydrate mitigation strategies, ensuring asset integrity while transitioning from MEG regeneration to more cost-effective, integrated hydrate and corrosion management approaches in offshore systems.