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C. Kanakaki, R. Kadnar, E. Rosenberg:
"Determination of Fluorinated Benzoic Acids Used as Organic Tracers in Petrochemical Exploration Studies by Gas Chromatography/Mass Spectrometry";
Poster: 9th Balaton Symposium on High-Performance Separation Methods, Siófok, Hungary; 04.09.2013 - 06.09.2013.

The needs of the petrochemical industry for more precise information on the characterization and understanding of the oil and gas reservoir geometry, and the flow patterns that are existing or may be induced in these reservoirs during exploitation, are continuously increasing. Many different characterization tools are nowadays available, such as production flow rates of reservoir fluids, four-dimensional (4D) seismic analysis, pressure measurements and tracing tests [1]. Interwell tracing techniques, involving multiple injection and production points, have proven to be the main useful tool in complex oil reservoirs, providing reliable, definitive and unambiguous information on flood patterns within the reservoir [2]. Many different types of water and gas tracers for both single and interwell tests have been used in the petroleum industry during the last decades, but the fluorinated benzoic acids (FBAs), like those examined in this work, are the organic tracers with the widest use, due to their favourable physico-chemical properties.
This work will discuss the determination of a large set of fluorobenzoic acids, based on a simple and efficient derivatisation technique, solid-phase extraction (SPE) for pre-concentration and analysis by gas chromatography/mass spectrometry (GC/MS). The derivatization reagent used in this study (trimethylsulfornium hydroxide, TMSH) is a suitable replacement for other derivatization reagents that are tedious or inconvenient to handle, and may produce reaction products unstable in water. Optimization of the individual steps of the method was performed and yielded a method that allows to quantitatively determine up to 14 different FBAs in one run, enhancing further the usefulness of the method, especially when interwell tracing tests are performed. Depending on the pre-concentration factor, the method provides a sensitivity down to the low ppb range for individual compounds which allows their efficient use in interwell tracer studies. Over the course of this research, we have also analyzed reservoir water samples spiked with the examined group of analytes, proving the robustness of the method for the particular matrix.


References
[1] C. Serres-Piole, A. Commarieu, H. Garraud, R. Lobinski and H. Preud´homme, Energy Fuels, 25 (2011) 4488-4496.
[2] Y. Du and L. Guan, Society of Petroleum Engineers Inc. (2005) SPE 93140.