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TitreAssessing pipeline vulnerability to telluric currents
AuteurBoteler, D H
SourceProceedings of CORROSION 2007; 2007 p. 1-16; 1 CD-ROM
Année2007
Séries alt.Secteur des sciences de la Terre, Contribution externe 20100350
RéunionCORROSION 2007; Nashville; US; mars 11-15, 2007
Documentlivre
Lang.anglais
MediaCD-ROM; numérique
Sujetsinterpretations telluriques; levés telluriques; champ tellurique; pipelines; établissement de modèles; géophysique; géologie de l'ingénieur
Illustrationsgraphs
ProgrammeTargeted Hazard Assessments in Northern Canada, Géoscience pour la sécurité publique
Résumé(disponible en anglais seulement)
Telluric currents produce variations in pipe-to-soil potential (PSP) that take the pipeline outside the voltage range for cathodic protection and interfere with potential surveys. The size of the PSP variation depends on a variety of factors related both to the natural environment and the characteristics of the pipeline itself. This paper presents a methodology for assessing how different pipeline features influence the vulnerability of the pipeline to telluric effects. Derivation of the distributed-source transmission line (DSTL) equations for induction in a pipeline show that the critical parameters are the series impedance of the pipeline steel and the parallel conductance to ground through the pipeline coating. Large PSP variations occur where there is a disruption in the flow of telluric currents along the pipeline, such as happens at the end of the pipeline, at flanges, at bends, and changes in pipeline characteristics. A series of plots are presented showing the dependence of PSP variations on coating conductance, changes in series impedance and bends in the pipeline. Also examined are how the PSP variations are modified when overlapping effects occur. Finally, the paper considers the effect of various mitigation strategies and presents model results of the reduction in PSP variations that can be achieved.
GEOSCAN ID287394