In this paper, we are presenting the results of the first quantitative study to characterize the initial interaction between acidic scale inhibitor and rock material during squeeze treatment. The precipitation of ferrous and calcium phosphonates was performed in batch experiments, under acidic conditions for a range of temperatures and ionic strengths. The stoichiometries of the precipitates, were found to be Fe1.25H3.5NTMP and Ca1.25H3.5NTMP, where NTMP is nitrilotris-(methylenephosphonic acid). Using a speciation model developed by Rice University, concentrations of free calcium, iron and phosphonate were calculates, from which the solubility product constants were derives as a function of temperature and ionic strength.

In addition, column experiments were performed to test the presence of these phases and the effects of iron ions on the retention of NTMP.

Subject
Acids, Precipitates, Phosphonates, Solids, Iron, Solubility, Calcium, Effluent, Acidity, Pores, Sodium chloride solution, Pumping, Corrosion inhibitors
Keywords:
calcium phosphonate, ferrous phosphonate, NTMP, crystal phase, squeeze treatment
© 2004 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).
2004
Association for Materials Protection and Performance (AMPP)
You do not currently have access to this content.