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Inspection of the Forties sea line
INSPECTION OF THE BP FORTIES SEA
LINE USING THE BRITISH GAS
ADVANCED ON-LINE INSPECTION
SYSTEM
FT IS ALMOST 20 years since British Gas formulated a policy for the
structural revalidation of its pipeline network using on-line inspection tech-
niques rather than the costly and disruptive method of hydrostatic pressure
testing. A research and development programme was undertaken which
culminated in the production of a range of advanced on-line inspection
devices based on the magnetic flux leakage technique.
These devices are now run at regular intervals through the company's
17,000km of high-pressure gas transmission pipelines, to monitor their
structural integrity. Following development and production of a range of
inspection vehicle sizes, British Gas now provides an inspection service to oil
and gas pipeline operators world-wide.
In 1987, an agreement was reached with BP to produce an inspection
system suitable for the 32-in diameter Forties main oil line. This required some
adaptation of the basic inspection sensing systems in order to accurately
locate, size and subsequently monitor a particular type of corrosion thought
likely to be found in the pipeline. This paper outlines the development work
carried out on the inspection system and the methods of reporting used to
assist BP in monitoring the condition of the pipeline.
INTRODUCTION
High-pressure steel pipelines have become strategically placed in many
countries as a means of energy transportation. Capable of handling enormous
volumes of gas and oil products, they are a significant factor in most
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