The growing demand of energy has resulted in a general need to produce fields with a significant CO2 content. The presence of corrosive species such as CO2, H2S, organic acids, chloride has a pronounced effect on corrosion in producing wells. For the last 25 years, the use of 13% Cr seamless steel tubing has been a cost effective solution for preventing sweet CO2 corrosion. More recently, Super 13% Cr alloys were introduced for improving the resistance to specific forms of corrosion, especially Sulfide Stress Cracking (SSC) at high yield strengths. They combine low carbon content and additions of Ni and Mo in order to achieve its superior properties over conventional 13% Cr steels.

This paper summarizes the results of electrochemical and SSC tests that were undertaken to assess the role of chloride content when combined with PH2S and pH in environments where SSC is likely to occur. NACE Uniaxial Tensile tests were performed according to the Fitness-For-Purpose approach recommended in the new edition of NACE MR0175/ISO 15156. The influence of the three parameters led to the creation of a three-dimensional mapping of SSC susceptibility on the whole range of yield strength. This mapping enables the definition of usage domains for Super 13% Cr stainless steel in sour service.

Subject
Hydrogen sulfide, Test methods, Materials, Secondary cracks, Sour environments, Sodium chloride, Tensile tests, Acidity, Sodium chloride solution, Corrosion resistance, Sulfide stress cracking, Chlorides, Corrosion potential
Keywords:
Super 13% Cr, Super martensitic stainless steel, modified 13% Cr, Sulfide Stress Cracking (SSC), depassivation pH, electrochemistry, fitness-for-purpose (FFP)
© 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)
You do not currently have access to this content.