Page 36 - Pipeline Pigging Technology

Available on-line technology

ON-LINE INSPECTION TECHNIQUES:

AVAILABLE TECHNOLOGY

IN-LINE inspection using "intelligent pigs" can now provide most, if not all,
of the information required about the condition of a pipeline, enabling the
operator to decide what must be done to rehabilitate it and the means
thereafter to regularly examine it to ensure it remains in good condition.
This paper examines the technology which is currently available, the
methods used, and provides an insight into some of the discussions which
surround them.

INTRODUCTION

Although an increasing number of pipelines have already reached the end
of their original design life, there is no reason why they cannot continue in
service provided their integrity can be properly and regularly monitored.
Whether the concern is that of risk assessment, rehabilitation or repair,
there is one fundamental requirement:

to accurately establish the present state of the pipeline.

Unless and until that is done, no decisions or plans can be made.
Clearly one of the first steps, then, is to carry out a detailed inspection
programme to obtain all the necessary technical data about the condition of
the pipeline. This information will be gathered from many sources, including
past records, but it will inevitably involve the use of a wide range of non-
destructive testing (NDT) methods.
Unlike most pressure vessels, a pipeline is usually only easily accessible at
each end. Onshore pipelines are usually buried and may run under roads,
rivers and railways. They may have access points at valve pits, but these may
be many miles apart.

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