There has been an increase in the use of high strength materials for production casings in deep water applications. It has been observed that some of these deep water wells contain small amounts of H2S. Consequently, the high strength casings in these wells also require sufficient sulfide stress cracking (SSC) resistance. Because the SSC resistance of materials generally decreases with an increase in strength, a fitness-for-service (FFS) approach that incorporates the effects of residual stress may provide a more realistic evaluation of the casing performance.

Large magnitudes of residual stresses are a by-product of manufacturing processes in steel casings. These stresses are understood to be tensile on the outer diameter (OD) and compressive on the inner diameter (ID). The compressive stress at the ID exposed to sour environment has the potential to delay propagation of crack-like defects by decreasing the crack propagation driving force. Therefore, characterizing the residual stress across the casing wall, and quantifying its effect on the crack propagation driving force, might be beneficial in reducing conservatism associated with the existing casing design approach.

Using multiple techniques to characterize through-thickness residual stress distribution, this paper explores the variability of residual stresses across samples of C110 casing. A numerical study is presented to assess the effect of residual stress on the crack propagation driving force.

Subject
X-ray diffraction, Materials, Piping, Modeling, Crack propagation, Measurement, Stress, Force, Flaws, Bending, Surface profile, Sulfide stress cracking, Residual stress
Keywords:
sulfide stress cracking, residual stress, driving force, fitness-for-service
© 2016 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).
2016
Association for Materials Protection and Performance (AMPP)
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