On-line inspection of pipelines using intelligent pigs constitutes a major aspect of corrosion control programs. The policy established by a petroleum operator is presented. It defines when base-line and early inspection surveys are considered necessary. The paper discusses the pros and cons of intelligent pigging operations and gives guidelines for deciding when to run in-service inspections to assess the condition of a pipeline and to verify the efficiency of corrosion control measures on a long term basis. It highlights factors like the estimated maximum corrosion rate, the positive change of actual corrosion allowance with time and the detection limits by the selected intelligent pigs.

In the second part, a recent experience concerning the base-line survey of the Lille-Frigg 10" wet gas production pipeline in the North Sea using an ultrasonic pig is presented. The inlet of this pipeline is situated at a subsea manifold.

The third part of the paper discusses aspects of intelligent pigging where difficulties are found and where improvements or new technological developments are needed.

Subject
Corrosion prevention, Piping, Manifolds, Intelligent pigs, Pipelines, Tools, Inspection, Corrosion detection, Liquids, Defects, Pigging, Corrosion protection, Surveys
Keywords:
intelligent pigs, on-line inspection, pipelines, CO2 corrosion, subsea manifold, corrosion control program, base-line survey, early inspection survey, condition assessment survey, ultrasonic pigs
© 1996 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
1996
Association for Materials Protection and Performance (AMPP)
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