 |
| Titel |
Organic geochemical characterization of reservoir rocks, cap rocks and formation fluids from the CO2 storage site at Ketzin, Germany |
| VerfasserIn |
A.-K. Scherf, D. Morozova, M. Wandrey, K. Mangelsdorf, H. Würdemann, A. Vieth |
| Konferenz |
EGU General Assembly 2009
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250025138
|
|
|
|
|
|
| Zusammenfassung |
| The European project CO2SINK (CO2 Storage by Injection into a natural saline Aquifer at
Ketzin) is the first project on the on-shore underground storage of carbon dioxide in Europe.
Near the city Ketzin (north-east Germany) a geological formation of the younger Triassic
(Stuttgart Formation) was chosen as reservoir for the long-term storage of the carbon
dioxide.
Within the scope of the Ketzin project we will analyse the organic matter in core rock and
fluid samples to investigate the biogeochemical effects and changes on the geological
formation caused by the injection of carbon dioxide. These investigations will help to
evaluate the efficiency and reliability of the long-term storage of CO2 in such a geological
system.
Organic geochemical analyses will be performed on core rock samples drilled in 2007 at the
Ketzin CO2 storage site in Germany. In total, three bore holes were constructed: one injection
well and two observation wells. In addition to the molecular analysis of the microbial
community we will investigate rock samples from different depths for total, dissolved and
extractable organic carbon including lipid biomarkers, such as organic acids and intact
polar lipids as well as the isotopic analysis of individual organic compounds. With
the analysis of intact phospholipids (IPL) we will be able to further characterize
the indigenous microbial community. Intact phospholipids are found in all living
cells as membrane components (Zelles, 1999). Their interpretation is based on
the premise that different microorganisms contain different phospholipids with
ester- and/or ether-bound fatty acids (White et al., 1979) and thus, the distribution
of IPLs and PLFAs (phospholipids fatty acid) can be applied to characterise and
compare microbial communities. The data obtained from these analyses will provide
valuable information on the active microorganisms as well as shifts in community
composition. The characterization of the organic matter in the reservoir rock allows
conclusion on the origin of the organic matter and the identification of potential
substrates as well as metabolites of the microorganisms within the reservoir and cap
rock.
Additional interest concerns the changes which occur due to the injection of carbon dioxide
into the geological formation. In June 2008 the injection of CO2 into the saline aquifer
near Ketzin started. From the biogeochemical point of view the injection of carbon
dioxide leads to the question which impact the storage may have on the existing deep
microbial ecosystem and reverse. In an earlier study on the underground storage of
carbon dioxide in the Frio Formation (USA) high DOC contents and increased
concentrations of organic acids in formation waters have been described after injection
of carbon dioxide (Kharaka et al., 2006). In Ketzin we will monitor changes in
the chemical composition of the formation waters within the reservoir by periodic
down hole sampling of the formation waters in the injection as well as the two
observation wells. These changes may affect the indigenous biocenosis according to e.g.
the availability of new carbon and energy sources. Possible subsequent changes
in the microbial community structure may affect the mineralogical structure in
turn.
Furthermore, it is planned to analyse core samples for their in-situ potential to release organic
compounds potentially mobilised by the injected carbon dioxide. This organic matter may
build up a new carbon pool which may be used by the microorganisms of the deep biosphere.
Considering this, microbial community changes in terms of abundance as well as
composition are conceivable.
References
Kharaka, Y.K. et al. (2006) Geology 34, 577-580.
White, D.C. et al. (1979) Oecolgia 40, 51-62.
Zelles, L. (1999) Biology and Fertility of Soils 29, 111-129. |
|
|
|
|
|
|