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

Abstract:

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.

• Periodical: Materials Science Forum (Volume 1139)
• Pages: 65-75
• DOI: https://doi.org/10.4028/p-RnPg4D
• Online since: December 2024
• Authors: Liyana Yasmin Azhar, Muhammad Hazman Hasnan, Husna Hayati Jarni, Norinsan Kamil Othman, Najmiddin Yaakob*
• Keywords: Bottom-of-Line Corrosion, FeS Layer, Internal Corrosion, Marginal Sour Corrosion, Pitting Rate

References

[1] "Annual Global Cost of Corrosion," insights global spec. https://insights.globalspec.com/ article/2340/annual-global-cost-of-corrosion-2-5-trillion

[2] "HSE Guideline for Pipeline Operators on Pipeline Anchor Hazards," in A guide to the Pipelines Safety Regulations, Health and Safety Executive, 2009.

[3] A. H. Moubaraki and I. B. Obot, "Top of the line corrosion: causes, mechanisms, and mitigation using corrosion inhibitors," 2021.

DOI: 10.1016/j.arabjc.2021.103116

[4] P.R. Roberge, "Handbook of Corrosion Engineering," 2nd edition.Washington D.C, 2012, p.1–54.

[5] C. J. Han, H. Zhang, and J. Zhang, "Failure pressure analysis of the pipe with inner corrosion defects by FEM," Electrochemical Science, 2016.

DOI: 10.20964/2016.06.6

[6] "Top of Line corrosion," Gate.energy, 2016. https://www.gate.energy/the-brainery/gat2004-gkp-2012-10/top-of-line-corrosion

[7] M. M. Azzam, "Failure Analysis of Pipelines in the Oil and Gas Industry," Pipeline Engineering, 2022.

[8] "Preventing Metal Corrosion," Minnesota Industrial Coatings, 2021. https://minnesotaindustrialcoatings.com/preventing-metal-corrosion/ (accessed Jan. 06, 2023).

[9] M. Seiersten, A. Dugstad, J. Nossen, and O. Sendstad, "Top of line corrosion in gas-condensate pipelines," 2021.

DOI: 10.1088/1757-899x/1201/1/012082

[10] Camacho A, Singer M, Brown B, and Nesic S, "'Top of the Line Corrosion in H2S/ CO2 Environments,'" in in Proc. Corrosion, Houston, TX, 2018, paper no. 08470, 2008.

[11] N. Yaakob, M. Singer, and D. Young, "Top of the Line Corrosion Behavior in Highly Sour Environments: Effect of the Gas/Steel Temperature," in Proc. Corrosion, Houston, TX, 2014, paper no. 3807, Houston], 2014.

[12] D. Vedapuri, C. Kang, D. Dhanabalan, and M. Gopal, "Inhibition of Multiphase Wet Gas corrosion," in Proc. Corrosion, paper No. 00043, Athens, 2000.

[13] G. Svenningsen, "'Sour Top of Line Corrosion: An Overview,'" Norway, 2015.

[14] W. Renpu, Oil and Gas Well Corrosion and Corrosion Prevention, 3rd edition., vol. 11. Elsevier Inc, 2011.

[15] K. A. Mohammed, "Ethylated Amine Role in the Inhibition of Top of Line Corrosion in Marginally Sour Environments," Oil and Gas Department, 2022.

DOI: 10.31663/tqujes.12.1.430(2022)

[16] Z. B. Wang, L. Pang, and Y. G. Zheng, "A review on under-deposit corrosion of pipelines in oil and gas fields," Corrosion Communications, 2022.

DOI: 10.1016/j.corcom.2022.03.007

[17] Y. P. Asmara, "The role of H2S gas in the behaviour of Carbon Steel Corrosion in Oil and Gas Environment," 2018.

[18] M. Singer, "Top of the line corrosion-Part 1: Review of the mechanism and laboratory experience," 2014.

[19] S. Nesic, Y. Zheng, B. Brown, and J. Ning, "Advancement In Predictive Modeling of Mild Steel Corrosion In CO₂ And H₂S Containing Environments," in in Proc. Corrosion, paper no. 6146, 2015.

DOI: 10.5006/1667

[20] Z. Ma, Y. Yang, B. Brown, S. Nesic, and M. Singer, "Investigation of FeCO3 and FeS Precipitation Kinetics by EQCM," in Proc. Corrosion, Houston, TX, 2018, paper no. 11192, 2018.

DOI: 10.1016/j.corsci.2018.06.017

[21] Y. Li, R. A. van Santen, and T. Weber, "High-temperature FeS-FeS2 solid-state transitions: Reactions of solid mackinawite with gaseous H2S," Solid State Chemistry, 2008.

DOI: 10.1016/j.jssc.2008.08.024

[22] Y. Wang, J. Li, C. Qu, W. Li, M. Baba Pali, and H. Zheng, "Corrosion of Oil and Gas Field Gathering Pipeline in H2S - CO2-Cl-System," IOP Publishing Ltd, 2020.

DOI: 10.1088/1755-1315/555/1/012046

[23] N. Yaakob, M. Singer, and D. Young, "Localized Top of the Line Corrosion in Marginally Sour Environments," in Proc. Corrosion, Houston, TX, 2016, paper no. 7695, 2016.

[24] M. Singer, "Top Of The Line Corrosion In Sour Environment – Study Of The Controlling Parameters," Athhes, Ohio, 2011.

[25] M. Achour, J. Kolts, P. Humble, and R. Hudgins, "Experimental Evaluation Of Corrosion Inhibitor Performance In Presence Of Iron Sulfide In CO2/ H2S Environment," in Proc. Corrosion, paper no. 08344, Houston, TX, 2008.

[26] M. Singer, B. Brown, A. Camacho, and S. Nesic, "Combined Effect of Carbon Dioxide, Hydrogen Sulfide, and Acetic Acid on Bottom-of-the-Line Corrosion," 2011.

DOI: 10.5006/1.3543715

[27] B. N. Brown, S. Nesic, B. Brown, and S. Reddy Parakala, "CO2 Corrosion in the Presence of Trace Amounts of H2S Localized corrosion of mild steel in slightly sour condition," in in Proc. Corrosion, paper no. 604736, 2014.

[28] C. Ren, D. Liu, Z. Bai, and T. Li, "Corrosion behavior of oil tube steel with hydrogen sulfide and carbon dioxide," Mater Chem Phys, vol. 93, no. 2–3, p.305–309, Oct. 2005.

DOI: 10.1016/j.matchemphys.2005.03.010

[29] ASTMG1-03, "Standard Practice for Preparing, Cleaning and Evaluating Corrosion Test," Phidelphia, PA. ASTM, Phidelphia, PA, 1999.

[30] ASTMG46-94, "Standard Guide for Examination and Evaluation of Pitting Corrosion," ASTM. Phildelpia, PA, 2018.

[31] M. A. Islam and Z. N. Farhat, "Characterization of the Corrosion Layer on Pipeline Steel in Sweet Environment," J Mater Eng Perform, vol. 24, no. 8, p.3142–3158, Aug. 2015

DOI: 10.1007/s11665-015-1564-4