Fitness for Purpose Assessment of Girth Weld Defect Based on In-Line Inspection

Abstract:

The girth weld defect is one of the most common types of defects on oil and gas pipelines, which can have a strong impact on the operation safety. Several girth weld failure accidents have occurred on PetroChina’s pipelines in recent years. In this paper, PetroChina’s current work on inspection and fitness for purpose assessment of girth weld defects is summarized. The in-line inspection has been proved to be the best practice for oil and gas pipeline defect inspection, but there are still some technical issues such as defect characterization and parameter selection. Fitness for purpose assessment methods for girth weld defects include strength assessment method based on plastic collapse, FAD method based on both plastic collapse and fracture, simplified factor method and numerical analysis method based on finite element. It is critical to identify the actual type of defects detected in in-line inspection to select an appropriate assessment method. The identification of various loads and the selection of appropriate material parameters are also important issues in assessment procedure. The key techniques to be developed include defect characterization, load identification, assessment of defects on high grade steel pipes, reliability-based assessment, etc.

• Periodical: Applied Mechanics and Materials (Volume 853)
• Pages: 524-528
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.853.524
• Online since: September 2016
• Authors: Jian Chen*, Zheng Qiang Lei, Fu Xiang Wang, Ting Wang, Ming Fei Li
• Keywords: Fitness for Purpose Assessment, Gas Pipeline, Girth Weld Defect, In-Line Inspection (ILI), Oil Pipeline

References

[1] F. Wang, Q. Feng, L. Zhou, Application Progress of Tri-Axial MFL Sensors Technology, Proceedings of the International Conference on Pipelines and Trenchless Technology 2011, pp.981-989.

DOI: 10.1061/41202(423)104

[2] W. Kastner, E. Röhrich, W. Schmitt, R. Steinbuch, Critical crack sizes in ductile piping. International Journal of Pressure Vessels and Piping, 1981(9): 197-219.

DOI: 10.1016/0308-0161(81)90002-8

[3] A. Cosham, P. Hopkins, The pipeline defect assessment manual (PDAM), Newcastle, UK, (2001).

[4] British standard, BS 7910, Guide on methods for assessing the acceptability of flaws in metallic structures, (2013).

[5] A. G. Miller, Review of limit loads of structures containing defects, International Journal of Pressure Vessels and Piping, 1998(23): 197-327.

DOI: 10.1016/0308-0161(88)90073-7

[6] Y. Wang, J. F. Swatzel, D. Horsley, A. Glover, Girth weld ECA from the perspective of code revisions in north America, Proceedings of 4th International Pipeline Conference, 2002, pp.677-689.

DOI: 10.1115/ipc2002-27167

[7] Y. Wang, D. Rudland, Development of Structural Integrity Assessment Procedures and Software for Girth-Welded Pipes and Welded Sleeve Assemblies, PRCI, (2010).

[8] API standard, API 1104, Welding of pipelines and related facilities, (2013).

[9] Canada standard, CSA Z662, Oil and gas pipeline systems, (2011).

[10] API/ASME standard, API 579-1/ASME FFS-1, Fitness-For-Service, (2007).

DOI: 10.1115/pvp2008-61796

[11] British Energy Generation Ltd., R6, Assessment of the integrity of structures containing defects, Rev. 4, (2001).

[12] SINTAP, Structural integrity assessment procedures for European industry, (1999).

[13] Chinese standard, GB/T 19624, Safety assessment for in-service pressure vessels containing defects, (2004).

[14] ASME XI IWB-3640 and Appendix C, Flaw evaluation procedures and acceptance criterion for austenic piping, (1986).

[15] ASME XI IWB-3650 and Appendix H, Flaw evaluation procedures and acceptance criterion for ferritic piping, (1992).

[16] C. Liu, Study of safety assessment method of piping containing circumferential planar defects, Ph. D. dissertation, East China University of Science and Technology, (1999).

[17] H. Aue, S. Paeper, B. Brown, High-quality geometry module data for pipeline strain analyses, Pigging Products and Services Association, (2007).

[18] B. Nyhus, M. L. Polanco, O. Ørjasæther, SENT Specimens An Alternative To SENB Specimens For Fracture Mechanics Testing Of Pipelines, Proceedings of 22nd International Conference on Offshore Mechanics and Arctic Engineering, (2003).

DOI: 10.1115/omae2003-37370

[19] D. Rudland and Y. Wang, Low-Constraint Testing of Pipeline Girth Welds, Proceedings of 2006 International Pipeline Conference, (2006).

DOI: 10.1115/ipc2006-10492

[20] B. Amend, Vintage girth weld defect assessment comprehensive study, PRCI, (2010).