Acids injected downhole for scale removal treatments are extremely corrosive to the production tubing and casing liners. Inhibitors are added to the stimulation fluids to minimize this corrosion. A laboratory method for screening the effectiveness of inhibitors is discussed in this paper. Parameters include acid type, metallurgy, temperature, inhibitor type and concentration, duration of acid-metal contact, and the effect of other chemical additives. Results obtained from a study utilizing conditions and fluids representative of the Prudhoe Bay Field (Eastern Operating Area) are given. The data indicate that, in general, 9%-Chrome, 1%-Molybdenum (9Cr-1Mo) metallurgy is more difficult to protect than low alloy carbon steel or 13%-Chrome (13Cr). HCl-HF mud acids require higher inhibitor concentrations than HCl for equivalent protection. The chrome alloys are more susceptible than carbon steel to pitting corrosion.

Subject
Acids, Acid concentration, Additives, Drilling fluid, Weight loss coupons, Stimulation, Fluids, Weight loss, Corrosion inhibitors, Steel, Corrosion protection, Corrosion coupons, Metallurgy
Keywords:
corrosion, inhibitor, stimulation acids, laboratory test, chrome alloys, carbon steel, Prudhoe Bay
© 1992 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).
1992
Association for Materials Protection and Performance (AMPP)
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