1. Regular removal of existing biofilms; 2. BIO addition to aid biological control during and after pigging; and 3. Continuous CI addition to protect the cleaned surfaces, after pigging and preferentially at a low dosage.
• •
The dosages of added chemicals need to be adjusted according to the characteristics and the dynamics in the given system. Chemicals and clean-in-place systems need to complement each other.
The chemical addition needs to be monitored to avoid unexpected changes with the age of the reservoir.
• Understanding the corrosion mechanism and the identification of the bacteria responsible for corrosion requires more detailed studies. This sets a demand for the application of combined methods that resolve the interaction of the microorganisms and their ecosystem, i.e. the biofilm, the underlying surface and the bulk water.2
On-site monitoring in dynamic flow-through systems in the field is the best solution. Aquateam has recommended to operators that an integrated microbial monitoring system is built into the water system offshore(
www.touchoilandgas.com/suppliers.cfm?supplier_id=2129 9&level=2), integrating the understanding of the operation of the injection water and the PWRI systems; if this is not possible or cost- efficient, laboratory studies simulating field conditions can be carried out.10
n Acknowledgements
This JIP was funded by the Research Council of Norway (Petromaks programme), BP Norway, Statoil ASA, Norske ConocoPhillips AS, Norske Shell AS, Total E & P Norway AS, Yara International ASA, YPF SA, and Aquateam AS Norway.
The Material and Corrosion Technology Group at the Institute for Energy Technology in Kjeller, Norway is thanked for providing parts of the corrosion monitoring data. This study was presented for the first time at the Oil Field Chemistry Symposium, 27–30 March 2011 in Geilo, Norway.
1.
Vik EA, Janbu AO, Garshol FK, et al., Nitrate based souring mitigation of produced water – side effects and challenges from the Draugen PWRI pilot. Paper number 106178-MS, Presented at: SPE International Symposium on oilfield chemistry, Society of Petroleum Engineers, Houston, Texas, USA, 28 February–2 March 2007.
2. 3. 4. 5. 6. 7. 8. 9.
Schwermer CU, Garshol FK, Vik EA, A Holistic Approach To Examine Microbially Influenced Corrosion In PWRI Based Systems, Presented at: International Symposium on Applied Microbiology and Molecular Biology in Oil Systems, Aarhus, Denmark, 17–19 June 2009.
Kielemoes J, de Boever P, Verstraete W, Influence of denitrification on the corrosion of iron and stainless steel powder, Environ Sci Technol, 2000;34:663–71.
Hubert C, Nemati M, Jenneman G, Voordouw G, Corrosion risk associated with microbial souring control using nitrate or nitrite, Appl Microbiol Biotechnol, 2005;68:272–82.
Schwermer CU, Lavik G, Abed RMM, et al., Impact of nitrate on the structure and function of bacterial biofilm communities in pipelines used for injection of seawater into oil fields, Appl Environ Microbiol, 2008;74:2841–51.
Jenneman GE, Blumer DJ, Harris JB, Corrosion and ‘Schmoo’ in Produced Water Systems, Exploration & Production – Oil & Gas Review, 2010;8(2):89–92.
Vik EA, Schmoo and Emulsions – Challenges Influencing the Selection and Operation of Produced Water Treatment, Exploration & Production – Oil & Gas Review, 2010;8(1):125–8.
Haaijer SC, Van der Welle ME, Schmid MC, et al., Evidence for the involvement of betaproteobacterial Thiobacilli in the nitrate-dependent oxidation of iron sulfide minerals, FEMS Microbiol Ecol, 2006;58:439–48.
Butler IB, Rickard D, Framboidal pyrite formation via the oxidation of iron (II) monosulphide by hydrogen sulphide, Geochim Cosmochim Acta, 2000;64:2665–72.
10. Garshol FK, Schwermer CU, Dinning AJ, Vik EA, Petromaks/JIP PWRI – reservoir souring mitigation and MIC control, Final report 2006 – 2010, Aquateam report no 10-041, 2010.
EXPLORATION & PRODUCTION – VOLUME 9 ISSUE 2 103
www.oilinwater.com Unique
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Sensor probe directly mounted into the water / process line
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