Page 175 - Pipeline Pigging Technology

Pipeline Pigging Technology

Fig.9.Pipcwall thickness statistics - maximum values - operation 2.
When the inspection vehicle was run in operation 2 (March, 1989), it was
important to assess the exact nature and extent of the girth weld corrosion
found in operation 1, and also to determine any "corrosion growth rate".
Having an assessment of this "corrosion growth rate" would allow BP to:

a) take steps to consider changing the operating conditions of the
pipeline;
b) to assess the long-term viability of the pipeline with respect to future
perceptions of throughput;
c) satisfy the appropriate regulatory authorities that all actions were
being taken to operate the pipeline in a safe manner.

The results obtained in operation 2 were therefore given as before, i.e.
listings of pipe-wall thickness and girth-weld corrosion severity. However, as
an additional aid to viewing and understanding the results, they were

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