Unexpected corrosion was being experienced in steel piping handling source-well brine used for secondary oil recovery. On-site analysis for dissolved H2S and CO2 gave results which predicted much lower rates than were observed on coupons and on linear polarization probes mounted in the flowlines. Cathodic polarization curves made on electrodes in the flowlines suggested a mild oxygen influence. Serial dilution bacteria bottle results suggested an additional MIC (microbiologically induced corrosion) influence.

Three components were therefore involved in this corrosion, dissolved acid gases, small oxygen concentration, and microbially influenced corrosion. A corrosion inhibitor was developed in the laboratory which controlled corrosion due to the first two factors. The ratio of CO2 to H2S, the influence of small amounts of added oxygen, and pre-corrosion were factors considered in this development.

Micro-biocide as well as corrosion inhibitor was applied to the field systems; serial dilution bottles indicated good kill. Coupons and linear polarization probes confirmed that corrosion rates became acceptably low.

Subject
Water, Inhibitor performance, Corrosion rate, Slopes, Iron sulfides, Iron, Bacteria, Corrosion inhibitors, Brines, Oxygen, Corrosion coupons, Linear polarization resistance, Electrodes
Keywords:
acid gas corrosion, oxygen accelerated corrosion, MIC, LPR, cathodic polarization curves, corrosion inhibitors
© 2004 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).
2004
Association for Materials Protection and Performance (AMPP)
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