Top-of-line corrosion (TOL-corrosion) is an issue for the Ormen Lange field development. Two sub sea production templates will be connected to two multiphase pipelines that transport the well fluid to shore. The templates are installed at 850 m water depth where the seawater temperature is between –2 and –1°C. The multiphase pipeline inlet temperature is 80°C. The formation water and gas contains acetic acid and other organic acids. The combination of high fluid temperature, sub zero seawater temperature and organic acid in the gas implies that TOL-corrosion will take place in multiphase pipelines, unless the water condensation and acetic acid concentration in the top of line is controlled.

Calculations are performed to find the water condensation rates and the thermal insulation required keeping the condensation rate at an acceptable level. Simulations are carried out to determine the acetic acid concentration in the condensing water. An experimental program on TOL-corrosion is carried out at temperature 30.65 and 85°C, CO, partial pressure 0.9 – 1.1 bar, condensation rate 0.006 – 0.41 ml/(m2·s) and acetic acid concentration 0 - 6 mM.

TOL-corrosion will be controlled by applying a coating that gives an overall heat transfer coefficient of maximum 40 W/(m2·K) and limiting the acetic acid concentration in the water condensing in the top of line to 4 mM.

Subject
Water, Piping, Corrosion rate, Protective films, Saturation, Walls, Condensation, Pipelines, Iron, Condensation rates, Condensed water, Film formation, Acetic acid
Keywords:
Top of line corrosion, MEG, acetic acid, condensation rate
© 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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