Injection water is typically batch treated with biocides to minimize biofouling. This paper describes a study with biofilm reactors to determine the biocidal effect of TetrakisHydroxyMethylPhosphonium Sulfate (THPS). The results demonstrate how operators can optimize their use of biocides by testing the effect of different treatment conditions, including concentrations, exposure time, and continuous versus batch treatment, on biofilm from oil field systems.

The tests were conducted using injection seawater and biofilms of test organisms from the Dan field in the Danish Sector of the North Sea. Four anaerobic biofilm reactors were operated in parallel to compare the effect of 30 and 60 ppm continuous THPS product treatment to a 2 h 800 ppm batch treatment and an untreated control. Biofilm activity was determined by Reverse Transcriptase qPCR (RT-qPCR), measurements of sulfate reduction rates (SRR) using radiolabeled 35SO42− and measurements of metabolite concentrations.

Sulfate-reducing Bacteria (SRB) were active in all four biofilm reactors at the end of the experimental period. Continuous biocide treatment with 30 and 60 ppm THPS product reduced SRR by a factor 2 and 4 compared to the untreated control. Sulfate reduction was only temporarily inhibited by the 800 ppm batch treatment as activity recovered after 1½ days.

Subject
Archaea, Water, Reactors, Biocide treatment, Sulfates, Dosages, Biofilms, Souring, Bacteria, Produced water, THPS, Biocides, Risk reduction
Keywords:
TetrakisHydroxyMethylPhosphonium Sulfate (THPS), molecular microbiological methods (MMM), qPCR, Reverse Transcriptase qPCR (RT-qPCR), sulfate reduction rates (SRR), cell specific activity (CSA) index, sulfate-reducing Bacteria (SRB), biofilm, Dan field, Danish Sector of the North Sea
© 2014 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).
2014
Association for Materials Protection and Performance (AMPP)
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