Institut für Geophysik
Prof. Dr. Michael Becken
Dr. Volkmar Schmidt

Corrensstraße 24 48149 Münster
Tel.: +49 251 83-33590
Fax: +49 251 83-36100

Current Projects

DESMEX: Deep electromagnetic sounding for mineral exploration

Magnetic and dielectric properties of salt rocks

Pipeline-EM: Utilizing impressed current cathodic protection for EM Exploration

Archäo-geophysikalische Erkundungen bei Nonnweiler / Saarland

DC-train: Electromagnetic imaging using fields emitted by railway lines

EDE: Telluric recording system

Advanced field course 2014: Magnetotelluric and Gravity survey in the Vaucluse, SE France



Pipeline-EM: Utilizing impressed current cathodic protection for EM Exploration


Principal Investigator: Prof. Dr. Michael Becken
Co-Investigator: Dr. Jörg Schmalzl
Research Associate: Tobias Lindau
Funding: Deutsche Forschungsgemeinschaft (DFG)
Period: 01/03/2013-28/02/2016
Project partners: Westnetz GmbH


Objectives:

Central Europe is criss-crossed by pipelines to transport water, gas and oil. Metal pipelines are routinely protected against electrochemical corrosion with a coating supplemented with a cathodic protection system. For pipeline integrity tests, the DC current is temporarily switched on and off. The switching scheme effectively generates time-varying electrical currents and induces secondary electric and magnetic fields in the subsurface, which decay spatially and temporally as a function of subsurface electrical resistivity. Here, we propose to measure and to analyze the induced electromagnetic fields generated by switched cathodic protection currents in order to determine the subsurface electrical resistivity structure in the upper few kilometers depth range. We concentrate on a test site in the Weserbergland, where we combine electric field array measurements of the induced electromagnetic field with detailed studies of the current distribution in the pipeline, i.e. the source current. Our cooperation partners from the Westnetz GmbH will provide results from pipeline integrity surveys conducted recently in the test area, as well as access to the technical installations of the cathodic protection system. In combination with additional DC electrical and magnetostatic measurements, this will allow us to determine the source current. For an interpretation of the array measurements, we will consider the transient time domain as well as the frequency domain response of the earth to the current injected into a pipeline structure and leaking inductively and, at grounding points and coating defects, galvanically into the ground. This approach is closely related to controlled source electromagnetics, and may provide a cheap complement to existing electromagnetic geophysical sounding techniques, which is applicable in noisy environments without facing the logistical challenge of the installation a strong current source in the field. The methodology can aid in geophysical subsurface reconnaissance addressed in the exploration and monitoring of resources, reservoirs and geological storages.

Pipeline-em

Ey-electric field component, recorded in the Wiehengebirge north of Osnabrück. a) Low-pass filtered time series at 128 Hz sampling rate, showing pulses superimposed on a varying background electric field. b) Zoom into the time series, showing pulse widths of 3 seconds and 12 seconds, respectively.

Publications and Conference contributions:

T. Lindau and M. Becken. Impressed pipeline currents for EM exploration. In: Proceedings of the 22nd EM Induction Workshop, Weimar, Germany, August 25-30, 2014.
M. Becken and T. Lindau. Utilizing Impressed Current Cathodic Protection as the Source for Electromagnetic Exploration. 76th EAGE Conference and Exhibition, Amsterdam. WS09 - CSEM: Where Do We Stand and Where Can We Go? 16 June 2014.
T. Lindau and M. Becken. First test measurements for utilizing Impressed Current Cathodic Protection of pipelines as a source for EM exploration. In: 74th DGG-Meeting, Karlsruhe, Germany, March 10-13, 2014.


Impressum | © 2015 Institut für Geophysik
Institut für Geophysik
Prof. Dr. Michael Becken
Dr. Volkmar Schmidt

Corrensstraße 24
· 48149 Münster
Tel.: +49 251 83-33590 · Fax: +49 251 83-36100
E-Mail: