Laboratory tests and field acidizing operations have been conducted on a 25% Cr-140 ksi duplex stainless steel utilizing a 90% HCl 15% + 10% CH3COOH acid mixture inhibited with a commercial package. Laboratory tests proved that the duplex stainless steel can be effectively protected in the adopted experimental conditions at 150°C. Examination of parts of tubings extracted from a real completion showed appreciable corrosion attack only in the sections of the string placed at higher depth (operating temperatures ~130°C): in these cases the estimated rates of corrosion attack can be about one order of magnitude higher than that foreseeable on the basis of laboratory tests. However even in these cases the severity of attack is maintained within acceptable limits.

Subject
Acids, Materials, Autoclaves, Acid attack, Micrography, Mixtures, Corrosion attacks, Tubing, Corrosion losses, Weight loss, Corrosion inhibitors, Steel, Duplex stainless steel
Keywords:
duplex, stimulation, acid mixture, inhibitors, oil wells
© 1995 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).
1995
Association for Materials Protection and Performance (AMPP)
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