Bottom of Line Corrosion Mechanism in Marginal Sour Environment Wet Gas Pipelines

• Published in: Materials Science Forum
• Main Author: Azhar L.Y.; Hasnan M.H.; Jarni H.H.; Othman N.K.; Yaakob N.
• Format: Book chapter
• Language: English
• Published: Trans Tech Publications Ltd 2024
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85213831727&doi=10.4028%2fp-RnPg4D&partnerID=40&md5=7bd131ec40f20cdce95f98d15ea7b9a7

Internal pipeline corrosion is a well-recognized issue in the oil and gas industry, especially in multiphase flow systems, such as wet gas transportation pipelines that contain mixed phases. Internal corrosion typically manifests as either top-of-the-line corrosion (TLC) or bottom-of-the-line corrosion (BLC). While corrosion mechanisms in sweet environments (dominated by CO₂) are relatively well-understood, those in sour environments (dominated by H₂S) remain less thoroughly examined. In sour environments, the primary corrosion product is iron sulfide (FeS), while in sweet environments, iron carbonate (FeCO₃) tends to form. In marginally sour conditions, FeS layers are often non-uniform, promoting localized corrosion and pitting because low concentration of H2S. It is hypothesizes that higher concentrations of H₂S reduce both the pitting rate and depth.The objective of this research is to investigate the corrosion rate, surface profile, and morphology in a marginal sour environment, using profilometry analysis (ASTM G46) to assess pitting. The experiments were conducted in a glass cell setup simulating pipeline conditions with 3 wt% brine solution and 1000 ppm acetic acid. Corrosion behavior was assessed at H₂S concentrations of 0 ppm, 30 ppm, and 80 ppm using weight loss analysis, surface morphology, and profilometry measurements. Results indicate that increasing H₂S concentration decreases the pitting rate, supporting the study’s hypothesis. © 2024 Trans Tech Publications Ltd, All Rights Reserved.