10113 Use of Geomagnetic Data for Evaluation of Telluric Effects on Pipelines

Tuesday, March 16, 2010: 8:05 AM
214 B (Henry B. Gonzales Convention Center)
Larisa Trichtchenko*, Peter Fernberg, and Myles Harrison
Geomagnetic Laboratory, Natural Resources Canada
Telluric currents interfere with cathodic protection system and cause variations in pipe-to-soil potentials, which can exceed the levels recommended for protection of pipeline steel. The amplitudes of the telluric currents observed in a pipeline depend on three factors: (1) the level of geomagnetic activity, (2) conductivity of the underlying Earth and (3) pipeline electromagnetic properties and geometric parameters. These factors have been incorporated into mathematical models that are used to estimate the pipe-to-soil variations due to the telluric activity. The complete simulation, based on the geomagnetic data from Canadian observatories, conductivity structures for the different regions of Canada and the pipeline model is used to provide an on-line space weather service for pipeline operations. This allows the user to evaluate the pipe-to-soil potential fluctuations at particular locations for a user-defined pipeline and correct results of pipeline potential surveys.The cumulative “unprotected” time can be different depending on pipeline location and telluric activity. To estimate the cumulative unprotected time statistical evaluations of telluric activity derived from geomagnetic data for 30 years has been performed. The resulting maps for different years and geographic locations and simple pipeline topology are presented in this paper. More detailed evaluations for complex pipeline routes can be done in the future.