Abstract:

Telluric effects associated with geomagnetic field variations cause currents to flow in burled pipelines, which present a continuing problem/or monitoring cathodfc protection. Protection methods Involving the application of a noncorrosive coating with cathodic protection should present the circulation of erratic currents. Nevertheless, often these currents cannot be compensated. During days of high geomagnetic activity, an excess of current that cannot be drained circulates along the pipe. This ejfect has a strong dependence on the electrical resistivity oj the host soil, produces a strong current channeling along the pipes, and Increases the risk of corrosion. A method was proposed to quantify the corrosion effects over the pipelines, assuming the geomagnetic field as the external source responsible for the erratic currents. Nondisturbed fields and geomagnetic storms were modeled and pipeline currents were calculated as a function of the characteristics of the soils and pipe sizes using a numerical code previously developed. © 1999, NAGE International.