Acidizing is frequently used as a method to stimulate the production of oil at the onset of production or in subsequent well workovers. For some formations, “mud acids” (e.g., HCl-HF solutions) are required. As these acid packages are quite corrosive to steels and corrosion resistant alloys (CRA’s), corrosion inhibitors must be added to minimize the attack on the downhole components throughout the period of the well stimulation. This paper presents and discusses the results of a laboratory study of the corrosion inhibition of 13Cr, Super 13Cr, and 15Cr martensitic stainless steel exposed to half strength mud acid solutions (7½ wt.% HCl +1½ wt.% HF) over the temperature range of 210°-250°F (99°-121°C). Several inhibitor packages were studied as additions to fresh and simulated spent acid packages. The Super 13Cr and 15Cr stainless steels were more difficult to protect against localized attack than the straight 13Cr, but it was demonstrated that these steels can be successfully protected from excessive general corrosion and pitting during their exposure during formation stimulation.

Subject
Acids, Pits, Inorganic inhibitors, Alcohols, Acid inhibitors, Materials, Inhibitor performance, Autoclaves, Kerosene, Fluids, Corrosion inhibitors, Stainless steel, Martensitic steel
Keywords:
Acidizing, martensitic stainless steel, 13Cr, Super 13Cr, 15Cr, production tubing, mud acid, HCl, HF, inhibition
© 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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