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TitleTelluric Influence on Pipelines
AuthorBoteler, D H; Trichtchenko, L
SourceOil and Gas Pipelines: Integrity and Safety Handbook; 2014.,
Alt SeriesEarth Sciences Sector, Contribution Series 20140162
PublisherJohn Wiley & Sons, Inc
Mediapaper; on-line; digital
File formatpdf
Subjectstelluric electric fields; pipeline-telluric interfere; geomagnetic sources; pipe-to-soil potentials (PSP); earth's deep conductivity structures
Illustrationsgraphs; plots
ProgramNorthern Canada Geohazards Project, Public Safety Geoscience
AbstractTelluric PSP variations have been observed on pipelines in many parts of the world and are a concern because interference to pipeline surveys and for creating conditions that may contribute to corrosion of the pipeline. The telluric activity originates from the activity on the Sun that causes geomagnetic disturbances at the Earth. The telluric electric fields enhanced due to these disturbances depend on the amplitude and frequency content of the geomagnetic field variations and on the deep Earth conductivity structure. Pipeline response to telluric electric fields is controlled by the electrical properties of the pipeline: the series impedance of the steel and the parallel admittance through the coating. Use of higher resistance coatings on modern pipelines has increased the size of telluric PSP variations that occur making telluric effects visible on pipelines all over the world. If telluric influence is suspected on a pipeline then a telluric hazard assessment can be made taking account of the geomagnetic activity, Earth structure, and pipeline characteristics to determine how often specified PSP levels will be exceeded in different parts of the pipeline. Mitigation now focusses on allowing telluric currents to flow along the pipeline and providing good ground connections to drain currents off the pipeline at the ends, bends, etc. Comparison with reference recordings can be used to correct survey data. Substantial work is required to properly evaluate the impact of telluric PSP fluctuations on pipeline corrosion and possible disbondment of coatings.
Summary(Plain Language Summary, not published)
Space weather refers to the dynamic conditions on the Sun and in the space environment, in particular, in the near-Earth environment, that can affect critical infrastructure. NRCan operates the Canadian Space Weather Forecast Centre and conducts research into space weather effects on power systems, pipelines, radio communications and GNSS positioning to help Canadian industry understand and mitigate the effects of space weather. To help engineers understand how telluric currents can affect pipelines, this book chapter provides a review of the literature followed by an explanation of the geomagnetic sources of telluric activity, the impacts of Earth¿s deep conductivity structures, and a pipeline's response to telluric electric fields. The chapter then describes the methodology for assessing telluric effects and mitigation/compensation of telluric effects and concludes by examining the knowledge gaps and open questions about telluric effects.