In order to precise the actual acidity of the corrosive media prevailing in the oil and gas wells where CO2 corrosion is encountered, a pH meter has been built which enables pH measurements under pressures from 0.1 up to 100 MPa.

The usual physical chemistry of calco-carbonic equilibria is also presented under a new form, which emphasizes better the influence of the partial pressure of CO2 as the controlling variable in the system.

It turns out from both theoretical and experimental results that the pH of a production water depends as much upon its so called alkalinity as upon the level of the CO2 partial pressure. The effect of calcareous saturation or supersaturation is also emphasized.

It is then shown by a survey on actual analyses of production waters that their acidity under well conditions is certainly much weaker than it is often said. This stands for both CO2 corrosion and sulfide stress cracking.

Subject
Water, Alkalinity, Saturation, Sodium chloride, Bicarbonates, Dissolution, Solubility, Calcium, Calcite, Partial pressures, Acidity, Sodium chloride solution, Electrodes
© 1982 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).
1982
Association for Materials Protection and Performance (AMPP)
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