This paper examines the effect of produced sand on the efficiency of the CO2 corrosion inhibitor chemicals used to protect oilfield carbon steel flowlines, topsides equipment, and export lines. A series of laboratory tests show that loss of typical commercial corrosion inhibitors from bulk fluids by adsorption onto the surface of sand particles can be a significant effect at high sand concentrations (>1000 ppm, i.e. >35 pounds per thousand barrels) especially if the sand is oil-wet and has a small particle size (< 10 micron diameter). Significant adsorption loss is also demonstrated onto gas / liquid interfaces in a foam showing that both gas / liquid and liquid / liquid interfacial area should be minimised in operations by good phase separation. Adsorption losses are insignificant for low sand concentrations (<35 pounds per thousand barrels). A stationary bed of sand covering a carbon steel surface does appear to inhibit general corrosion but is likely to increase the risk of localised corrosion in the medium to long term.

Subject
Steel surfaces, Cylinders, Sand, Corrosion rate, Inhibitor films, Adsorption, Liquids, Corrosion losses, Interfaces, Corrosion inhibitors, Brines, Electrodes, Oil
Keywords:
sand, corrosion inhibitor, adsorption, foam, interface, erosion
© 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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