The cathodic protection systems of two platforms installed by Conoco Netherlands in the Southern North Sea were based on accepted design criteria. The use of elongated anodes resulted in high initial current densities that polarized the structures well beyond the minimum protective potential. The results of surveys carried out a few months and one year after installation are presented and discussed. An initial platform current density of the order of 30 mA/ft2 (320 mA/m2) polarized the structures to -0.95 V with respect to the silver/silver chloride reference electrode. It is shown that this initially high current density allows for lowering the maintenance current density. Cost effectiveness will be reflected in a markedly reduced anode weight requirement, and added insurance to obviate any need for premature refrofit.

Subject
Galvanic anodes, Anode potential, Anodic protection, Cathodic protection, Structures, Anode resistance, Negative potentials, Current densities, Anodic current, Surveys, Polarized potential, Electrode potential, Anodes
© 1987 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).
1987
Association for Materials Protection and Performance (AMPP)
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