Barium sulfate (BaSO4) scale formation is a long recognized and costly problem in oil production operations. Unlike calcium carbonate (CaCO3), significant amounts of BaSO4 cannot be dissolved by treatment with acids. Thus, the primary means of removal has traditionally been with mechanical means.

Chemical formulations have been developed which are capable of dissolving BaSO4 scale. One of these dissolver chemicals is shown to be capable of dissolving moderate amounts of BaSO4 as a function of temperature, concentration of chemical and contact time. Among other important factors are the composition of scale and the formulation of the chemical, but these factors were not investigated in this report. The dissolving ability is not analogous to acid dissolution of CaCO3 and therefore this chemical dissolver has more specialized applications. Several case histories of successful applications of this chemical dissolver are presented.

Related to the removal of BaSO4 scale is the prediction of its formation using water stability indices. A novel graphical method of BaSO4 scale prediction is described. The graphical representation is useful to visualize how the different parameters (e.g., ionic concentrations, ionic strength, temperature) influence BaSO4 scale formation. It allows for a simple and convenient determination of the tendency for BaSO4 scale formation and an estimation of the amounts of BaSO4 that could be precipitated.

Subject
Acids, Water, Permeability, Steel coupons, Dissolution, Barium, Solutions, Dissolvers, Fluids, Scale formation, Scale, Scaling, Cleaning
Keywords:
Scale, chemical, dissolution, prediction, barium sulfate
© 1992 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).
1992
Association for Materials Protection and Performance (AMPP)
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