Thermodynamic calculations show that the H2S solubility in aqueous solution, at a given H2S partial pressure, will be significantly reduced, compared to ambient pressure values, when exposed to high pressure CH4. This reduced H2S solubility suggests that current laboratory-based limits on the H2S partial pressure, PH2S, may be excessively high for use of low alloys steels and corrosion resistant alloys in high pressure gas and oil wells. Laboratory tests at lower PH2S, but with the aim of matching the H2S concentration to the calculated field value, have been proposed. The results of laboratory tests designed to verify this proposal have been made. The calculated decrease in the solubility of H2S at 341 bar (5000 psi) CH4 was confirmed. Two tests with low alloy steel confirmed some benefit, but less than projected. A test with a martensitic stainless steel showed no benefit. Experimental parameters that may have influenced these test results are identified.

Subject
Hydrogen sulfide, Test methods, Hydrogen concentration, Autoclaves, Hydrostatic pressure, Solubility, Gas pressure, Aqueous solutions, Ambient barometric pressure, Fugacity, Localized corrosion, Sulfide stress cracking, Stress corrosion cracking
Keywords:
sulfide stress cracking, H2S, methane, fugacity, C-110, 13Cr
© 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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