The HPHT (High Pressure High Temperature) Kristin field in the Norwegian Sea has an inlet design temperature for the flowlines of 155°C (310°F). The insulated reelable flowlines are made from SMSS (Super Martensittic Stainless Steel). The flowlines are insulated to provide a U-value of 8 W/m2K to allow the well stream to cool down to be acceptable for the flexible risers.

Several options for reelable coatings were investigated: high temperature (polysulphone) polymer materials as thermal barrier, polyurea, high temperature rubbers, “ductile” high temperature foams, five layer polypropylene foam and five layer polypropylene foam with a thermal barrier of polyamide.

An extensive qualification testing program was carried out to find the optimum candidates including screening tests of candidate insulation in water at elevated temperatures, ageing testing in sea water bath at elevated temperatures and bend testing to simulate reeling.

Only the five layer polypropylene foam was found to satisfy all qualification requirements and was recommended for use in the project.

Subject
Test methods, Barriers, Steel surfaces, Water, Materials, Piping, Insulation, Polypropylene, Fusion bonded epoxy coating, Flowlines, Polyamides, Steel, High temperature
Keywords:
Flowlines, Thermal Insulation, HPHT, Material qualification
© 2005 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).
2005
Association for Materials Protection and Performance (AMPP)
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