A laboratory inhibitor selection study was conducted to select suitable corrosion inhibitors for managing corrosion in wet sub-sea pipelines containing ethylene glycol / salt water fluid mixtures. Several inhibitors were screened using static autoclave partitioning tests simulating worst case field conditions at 248 kPa (36 psi) CO2 partial pressure and 75 ° C (167 F). All inhibitors studied afforded excellent protection against general corrosion but three chemistries were also very effective in preventing pitting attack. Uninhibited lean (~ 20% water content) and rich ( ~ 50% water content) ethylene glycol/water mixtures (MEG) were also studied under static and dynamic flow conditions to evaluate pitting corrosion tendency of sodium chloride salt spike (750 ppm, 5,000 ppm, 8,000 ppm and 80,000 ppm chloride) additions to theMEG relative inhibited fluids.
Key Words: wet sub sea pipeline, CO2 corrosion, salty ethylene glycol, corrosion control, hydrate control