HR: 1340h
AN: H23A-1131    [Abstracts]
TI: Electrometrical Methods Application for Detection of Heating System Pipeline Corrosion
AU: * Vetrov, A
EM: anton_vetrov@mail.ru
AF: Saint-Petersburg State University, Department of Geophysics, 7/9, Universitetskaja emb., Saint - Petersburg, 199034 Russian Federation
AU: Ilyin, Y
AF: Saint-Petersburg State University, Department of Geophysics, 7/9, Universitetskaja emb., Saint - Petersburg, 199034 Russian Federation
AU: Isaev, V
AF: DIsSO, 130, k. Griboedova, Saint - Petersburg, 199000 Russian Federation
AU: Rondel, A
AF: DIsSO, 130, k. Griboedova, Saint - Petersburg, 199000 Russian Federation
AU: Shapovalov, N
AF: DIsSO, 130, k. Griboedova, Saint - Petersburg, 199000 Russian Federation
AB: Coated steel underground pipelines are widely used for the petroleum and gaze transportation, for the water and heat supply. The soils, where the pipelines are placed, are usually highly corrosive for pipe's metal. In the places of crippling of external coating the corrosion processes begin, and this can provoke a pipe breakage. To ensure the pipeline survivability it is necessary to carry out the control of pipeline conditions. The geophysical methods are used to provide such diagnostic. Authors have studied the corrosion processes of the municipal heating system pipelines in Saint-Petersburg (Russia) using the air thermal imaging method, the investigation of electromagnetic fields and spontaneous polarization, measurements of electrode potentials of metal tubes. The pipeline reparation works, which have been provided this year, allowed us to make the visual observation of pipes. The investigation object comprises a pipeline composed of two parallel tubes, which are placed 1-2 meters deep. The fact that the Russian Federation and CIS countries still use the direct heat supply system makes impossible any addition of anticorrosion components to circulating water. Pipelines operate under high pressure (up to 5 atm) and high temperature (designed temperature is 150øC). Tube's isolation is meant for heat loss minimization, and ordinary has poor hydro-isolation. Some pipeline construction elements (sliding and fixed bearings, pressure compensators, heat enclosures) are often non-isolated, and tube's metal contacts with soil. Hard usage condition, ingress of technical contamination cause, stray currents etc. cause high accidental rate. Realization of geophysical diagnostics, including electrometry, is hampered in a city by underground communication systems, power lines, isolating ground cover (asphalt), limitation of the working area with buildings. These restrictions form the investigation conditions. In order to detect and localize isolation (coat) defects authors successfully use the excitation-at-the-mass method measurement together with the measurements of magnetic and electrical components of electromagnetic field. However, the electrical contact between a tube and the soil, as well as the presence of zones of isolation defects is not the direct indicators of corrosion focus places. Authors use the spontaneous polarization method to investigate electrical fields, caused by natural electromotive forces of electrochemical origin. Different types of EM and SP anomalies have been detected. After statistical study and visual observations of extracted pipes, the relations between such anomalies and pipeline condition have been obtained. The places of underground pipeline coat destruction can be specified by complex of geophysical investigations. Also, it is possible to detect the intensity of destruction and corrosion processes in real time.
DE: 9810 New fields (not classifiable under other headings)
DE: 0600 ELECTROMAGNETICS
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting