Nitrate treatment is well documented as a mitigation method for reservoir souring, however, field trials have indicated that increased corrosion could be a possible side effect of nitrate treatment. This paper describes results from offshore side stream test rigs and laboratory investigation where a mixture of produced water and aquifer water was treated with nitrate. A corrosion rig was developed where the different combinations of produced water and Utsira aquifer water were investigated with respect to corrosion and microbial activity under offshore conditions. Corrosion increased when nitrate was added in combination with CO2, from 0.01 to > 1 mm year. The microbial community changed when nitrate was added, and the presence of H2 consuming bacteria indicates that a cathodic reaction could be a possible corrosion mechanism.

Subject
Water, Corrosion rate, Aquifers, Microbial activity, Biofilms, Nitrates, Bacteria, Oilfields, Produced water, Corrosion probes, Carbon steel, Electrical resistance probes, Linear polarization resistance
Keywords:
Utsira, aquifer water, microbial activity, corrosion, methanogens, nitrate
© 2007 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).
2007
Association for Materials Protection and Performance (AMPP)
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