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Electrical voltages and resistances measured to inspect metallic cased wells and pipelines

United States Patent

June 10, 2003
View the Complete Patent at the US Patent & Trademark Office
A cased well in the earth is electrically energized with A.C. current. Voltages are measured from three voltage measurement electrodes in electrical contact with the interior of the casing while the casing is electrically energized. In a measurement mode, A.C. current is conducted from a first current carrying electrode within the cased well to a remote second current carrying electrode located on the surface of the earth. In a calibration mode, current is passed from the first current carrying electrode to a third current carrying electrode located vertically at a different position within the cased well, where the three voltage measurement electrodes are located vertically in between the first and third current carrying electrodes. Voltages along the casing and resistances along the casing are measured to determine wall thickness and the location of any casing collars present so as to electrically inspect the casing. Similar methods are employed to energize a pipeline to measure the wall thickness of the pipeline and the location of pipe joints to electrically inspect the pipeline.
Vail, III; William Banning (Bothell, WA), Momii; Steven Thomas (Mercer Island, WA)
Western Atlas International, Inc. (Houston, TX)
09/ 813,272
March 19, 2001
This invention was made with Government support under DOE Grant No. DE-FG06-84ER13294, entitled "Validating the Paramagnetic Logging Effect", Office of Basic Energy Sciences, of the U.S. Department of Energy. The government has certain rights in this invention. The basic concept for the invention described herein was conceived during the funding provided by the above grant.