Metallurgical failure analysis of low carbon steel pipeline ASTM A106 in oil and gas field

• A. Magdy^1,2, M.A. Elhelaly^2,3, Z.A. Al-Saady⁴, Q.Q. Almajedi⁵, A.B. ElDeeb¹, E.S. Mosa¹, S. Salman¹ and A.A. Mahdy¹

¹ Mining, Metallurgy and Petroleum Engineering Department, Al-Azhar University, Nasr City 11371, Cairo, Egypt
² Corrosion Specialist, Zubair Oil Field, Bonatti, Basra, Iraq
³ Heat Treatment Department, Tabbin Institute for Metallurgical Studies, Helwan, Cairo, Egypt
⁴ Engineering Inspection & Asset Integrity Manager, Zubair Field Operating Division ZFOD, Basra, Iraq
⁵ Corrosion and plant integrity section head, Zubair Field Operating Division ZFOD, Basra, Iraq

Abstract: This article aims to investigate the failure caused by severe pitting corrosion, resulting in multiple leakages in a produced water pipe from the first separation stage of crude oil production. Produced water typically contains a high concentration of soluble salts and sediments. This fluid, which may be discarded or reused, is usually transported by low-carbon steel seamless pipes; in our study, ASTM A106 grade B was used. An examination of the failed parts included a thorough visual inspection, microstructural characterization using a light optical microscope (LOM), and field emission scanning electron microscopy (FE-SEM) with energy dispersive spectroscopy (EDS) of the corrosion products. Additionally, X-ray diffraction (XRD) analysis was performed to understand the nature of the failure and to suggest preventive solutions. Visual observations revealed a significant reduction in pipe thickness and the presence of numerous holes, while metallographic studies showed a high concentration of bacteria and salts on the inner surface. The results indicated that the primary cause of the low-carbon steel pipe failure was a low fluid flow velocity of 0.08 m/s (stagnant) combined with microbiological corrosion from sulfate-reducing bacteria (SRB).

Keywords: low carbon steel, localized corrosion, sulphate-reducing bacteria SRB, FE-SEM, XRD

Int. J. Corros. Scale Inhib., 2025, 14, no. 1, 19-37
doi: 10.17675/2305-6894-2025-14-1-2

Download PDF (Total downloads: 87)

Back to this issue content: 2025, Vol. 14, Issue 1 (pp. 1-... (in progress))