Failure Analysis for Girth Weld of Gathering Pipelines

Abstract:

Through failure generalization, fracture feature analysis and material performance test, a comprehensively analysis was made on the fracture failure analysis for girth weld of gathering pipelines containing H₂S gas. The results showed that the fracture failure might be mainly due to sulfide stress cracking in the girth weld. The crack originated from the fusion line on the inner surface of girth weld and extended along the girth weld to outside closed to bends. The sulfide stress cracking of the girth weld was caused by the intersection of multiple factors. The service condition was located in SSC 3 zone and the SSC risk of girth weld was high. The girth weld itself was not been stress-relieved, and its ability to resist SSC was poor. Due to low wall thickness, welding defects, welding stress and additional load, the actual stress of weld was higher.

• Periodical: Materials Science Forum (Volume 1035)
• Pages: 480-485
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.1035.480
• Online since: June 2021
• Authors: Fa Gen Li*, Quan Feng, An Qing Fu, Rui Cai
• Keywords: Fracture Failure Analysis, Gas Gathering Pipelines, Girth Weld, Stress Concentration, Sulfide Stress Cracking, Transition Cuts

References

[1] Hu Yongbi, Gu Tan. Corrosion features and corrrosion crontrol technologies in high-sulfur gas fields. Natureal Gas Industry, 2012, 32(12) : 92-96.

[2] Shan Guangbin, Liu Xiaohui, Qi Jing, at el. Failure Analysis of Natural Gas Pipeline. Pressure Vessel Technology, 2013, 30(11): 47-51.

[3] Sun Jiewen, Zhan Xiaolin, Yao Fei, at el. Cause Analysis for Cracking of Hydrogen Gas Pipeline. Surface Technology, 2016, 45(2): 50-56.

[4] Qiao Xianyi. Failure Analysis about Joint Pipes for Natural Gas End Station. Pressure Vessel Technology, 2012, 29(3): 59-64.

[5] SY/T 0611: Requirements of controlling internal corrosion in gathering pipeline system for highly hydrogen sulphide gas field, (2008).

[6] ISO 15156-2: Petroleum and natural gas industries-Materials for use in H2S-containing environments in oil and gas production-Part 2: Cracking-resistant carbon and low alloy steels, and the use of irons, (2015).

DOI: 10.3403/30302823

[7] EFC Publication No.16, Guidelines on materials requirements for cabon and low alloy steels for H2S-containing environments in oil and gas production.

DOI: 10.1201/9780429273858-7

[8] GB/T 9711:Petroleum and natural gas industries-Steel pipe for pipeline transportation systems, (2011).

[9] SY/T 5257: Steel bends for oil and gas transmission, (2004).

[10] SY/T 4103:Welding and acceptance standard for steel pipings and pipelines, (2006).

[11] Fu Anqing, Li Fagen Yin Chenxian, et.al. The detection project of gas gathering. Xi'an, CNPC Tubular Goods Research Institute, (2016).

[12] NACE TM 0177:Laboratory Testing of Metals for Resistance to SulfideStress Cracking and Stress Corrosion Cracking in H2SEnvironments, (2016).

[13] ISO 7539-2: Corrosion of metals and alloys-Stress corrosion testing-Part 2: Prepartation and use of bent-beam specimens, (1989).

DOI: 10.3403/00578567u

[14] SY/T 0599:Metallic material requirements on resistance to sulfide stress crackingand stress corrosion cracking for natural gas surface equipment, (2006).