Managing leaks from corroded pipelines with a pro-active plan to find and repair thinned sections in advance of failure

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Managing leaks from corroded pipelines with a pro-active plan to find and repair thinned sections in advance of failure

Vajpayee, Ankit / Russel, David

Most cast iron, ductile iron and steel pipelines in the industrialized world are at or nearing their design life. Leaks and breaks are daily occurrences and often lead to property damage, injuries and sometimes in loss of life. The U.S.D.O.E. has mandated that pipelines carrying flammables through populated area must be inspected or tested by destructive means to determine their condition. Electromagnetic tools have long been used for the inspection of large O&G pipelines, and recently the tools have been miniaturized for inspection of smaller lines, including those for water and waste water. The in-line inspection of pipelines has been the domain of magnetic flux leakage (MFL) tools for half a century; however, there are many pipelines that cannot be inspected with MFL tools. Internal scale and deposits in water and sewer pipes; wax and low-flow conditions in oil pipelines; elbows and pipes with multiple diameters can be insurmountable challenges for MFL tools. For the past decade, Remote Field Technology (RFT) has been increasingly applied in these challenging conditions with good success. This paper discusses the history, basic principles of RFT and describes several case studies where RFT has been successfully used to do condition assessment of oil & gas, raw water, potable water and waste water pipelines for corrosion, through thick liners and scale. MFL, ECT and RFT are compared for their respective strengths and limitations.