The Effect of Oxygenated Methanol on Corrosion of Carbon Steel in Sour Wet Gas Environments

Abstract Methanol is commonly used in the oil industry as a thermodynamic hydrate inhibitor. In world regions with extended winter seasons, significant amounts of methanol are injected into wells and pipelines. Previous studies have demonstrated that the presence of methanol in sour conditions can lead to higher corrosion rates and the increased susceptibility to sulfide stress cracking (SSC) in pipeline steel. Another problem is oxygen intrusion by dissolution in methanol, increasing corrosion rates and potential for localized corrosion. This paper studies the effect of oxygen in methanol on the structures and growth kinetics of iron sulfide scales. Gravimetric weight analysis was used to evaluate the corrosion mechanisms and rates. Scanning Electron Microscope/Energy Dispersive X-ray Spectrometry (SEM/EDX), Optical Microscope and X-ray Diffraction (XRD) were used to analyze the scale.