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| Titel |
Preliminary carbon and oxygen isotope results from CO2 injection at the Ketzin site |
| VerfasserIn |
V. Becker, A. Myrttinen, H. Würdemann, D. Morozova, M. Zimmer, P. Blum, P. Grathwohl, H. Taubald, J. A. C. Barth, CO2SINK Group |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250027153
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| Zusammenfassung |
| Stable carbon isotopes may serve as useful tracers for injected CO2 in the subsurface. This is especially true if the already present dissolved inorganic carbon (DIC) has a different isotopic composition (δ13CDIC) than the injected CO2. After dissolution of the latter, mixture of both pools can thus enable mass balance calculations to quantify ionic trapping of the injected CO2. In addition, since both water and CO2 contain oxygen, it is possible that the oxygen isotope composition of the water changes, if large amounts of CO2 are in contact with the water. Isotopic equilibration between both phases would provide an additional useful isotope tracer. Preliminary isotope measurements before and after injection of CO2 at the Ketzin site revealed good correlation between increasing DIC contents and its isotopic composition. The latter was as negative as -35 permille compared to values ranging between -4.2 and -5.6 permille before injection. On the other hand, the stable isotopic compositon of the water (δ18OH2O) remained relatively homogeneous with little variations, thus indicating that equilibration between CO2 and water --if any-- did not yet occur several weeks after injection. Preliminary data will have to be confirmed with samples from more frequent and robust sampling and preservation strategies. Particularly other geochemical data including ion- and organic matter contents, as well as pH measurements need to be combined with isotope data to understand subsurface processes and to quantify ionic trapping.
Keywords: monitoring of CO2 dissolution, stable isotopes |
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