The Oseberg 'B' steel jacket is an eight-legged jacket with a design life of forty years. In order to reduce weight a corrosion protection system combining aluminium anodes and coal tar epoxy coating was chosen. The entire jacket is coated. Anode selection was based on experiments designed to detect possible tendencies to passivation during the period of low current consumption. Cylindrically shaped anodes of the Al-Zn-In type were chosen since they would give the lowest possible weight, reduce the drag forces on the jacket and also have the lowest probability of passivating. A permanent monitoring system was installed consisting of 20 pairs of reference electrodes and shunted anodes. Such a system simplifies offshore surveillance of the c.p.-system, and also gives early warnings in case of anode passivation. Results of monitoring the potential from the day of launch are presented. The jacket potential reached the protective potential in the course of the first few hours.

Subject
Electric current, Galvanic anodes, Anode potential, Zinc anodes, Current densities, Anodic current, Steel, Corrosion protection, Jackets, Protection potential, Electrodes, Electrode potential, Anodes
© 1989 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).
1989
Association for Materials Protection and Performance (AMPP)
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