94. EMAT Lessons Learned Using Direct Assessment Findings
Matthew Romney1, Kayla Stark Barker1, Ron Lundstrom1, Daniel Bruce2, Alireza Kohandehghan3
1T.D. Williamson, Salt Lake City, USA. 2Pacific Northern Gas, Terrace, Canada. 3Pacific Northern Gas, Vancouver, Canada
Different cracking mechanisms can potentially affect pipelines depending on the operating conditions, product, coating type, pipe manufacturing process, and environment. These mechanisms include manufacturing-related crack-like linear indications (e.g., seam weld lack of fusion, subsurface or surface breaking laminations), construction-related cracks (e.g., girth weld cracks, in-service fillet weld toe cracks), cracks formed in mechanical damages, and environmentally assisted cracking (EAC). One of the most important forms of EAC relevant to pipeline structures is stress corrosion cracking (SCC) that has been of particular focus in the past two decades.
Due to the severe consequence of linear indication-related pipeline failures and nonlinear growth and propagation of specific types of linear indication integrity threats, pipeline operators continuously push for new technologies, methods, and procedures for assessing and mitigating pipeline integrity risks pertaining to crack and crack-like anomalies. Inline inspection (ILI) is proven as one of the most effective means that leads to significant improvement in the integrity management of these threats. A key ILI technology that has proven useful for the detection, classification, and sizing of gas pipeline crack and crack-like features is Electromagnetic Acoustic Transducer (EMAT) technology.
Understanding how technologies works and how their performance can be improved is of essence to the success of an ILI-based integrity management program. This article will present and discuss Pacific Northern Gas Ltd. (PNG), and T.D. Williamson (TDW) lessons learned, challenges, and successes of utilizing EMAT ILI technology to identify, classify, quantify, and mitigate crack and crack-like integrity threat risks across multiple gas pipeline systems. Utilizing an EMAT system, populations of anomalies will be reviewed and compared with direct assessment findings. Recommendations and potential mitigation strategies will also be presented.
Keywords: cracks, deformation, electromagnetic acoustic transducer, environmentally assisted cracking, gas pipeline, geometry, inline inspection, magnetic flux leakage, metal loss, Multiple Dataset, pipeline integrity, stress corrosion cracking, , DEF, EAC, EMAT, GEO, ILI, LFM, MDS, MFL, SCC, SMFL
