 |
| Titel |
Analysis of active microorganisms and their potential role in carbon dioxide turnover in the natural gas reservoirs Altmark and Schneeren (Germany) |
| VerfasserIn |
Claudia Gniese, Thomas Muschalle, Martin Mühling, Janin Frerichs, Martin Krüger, Andrea Kassahun, Jana Seifert, Nils Hoth |
| Konferenz |
EGU General Assembly 2010
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250032292
|
|
|
|
|
|
| Zusammenfassung |
| RECOBIO-2, part of the BMBF-funded Geotechnologien consortium, investigates the
presence of active microorganisms and their potential role in CO2 turnover in the formation
waters of the Schneeren and Altmark gas fields, which are both operated by GDF SUEZ E&P
Germany GmbH.
Located to the north west of Hannover the natural gas reservoir Schneeren is composed of
compacted Westfal-C sandstones that have been naturally fractured into a subsalinar horst
structure. This gas field is characterized by a depth of 2700 to 3500m, a bottom-hole
temperature between 80 and 110Ë C as well as a moderate salinity (30-60g/l) and high sulfate
contents (~1000mg/l). During RECOBIO-1 produced formation water collected at wells in
Schneeren was already used to conduct long term laboratory experiments. These served to
examine possible microbial processes of the autochthonous biocenosis induced by the
injection of CO2 (Ehinger et al. 2009 submitted). Microorganisms in particular
sulfate-reducing bacteria and methanogens were able to grow in the presence of
powdered rock material, CO2 and H2 without any other added nutrients. The observed
development of DOC was now proven in another long term experiment using labelled
13CO2.
In contrast to Schneeren, the almost depleted natural gas reservoir Altmark exhibits an
average depth of 3300m, a higher bottom-hole temperature (111Ë C to 120Ë C), a higher
salinity (275-350g/l) but sulfate is absent. This Rotliegend formation is located in the
southern edge of the Northeast German Basin and is of special interest for CO2 injection
because of favourable geological properties.
Using molecular biological techniques two types of samples are analyzed: formation
water collected at the well head (November 2008) and formation water sampled in situ from a
depth of around 3000m (May 2009). Some of the wells are treated frequently with a foaming
agent while others are chemically untreated.
Despite the extreme environmental conditions in the Altmark gas field, RNA of
apparently active microorganisms was successfully extracted from all samples. Sequence
analysis of 16S rRNA revealed mainly fermentative bacteria belonging to the phylogenetic
group of Actinobacteria (e.g. Propionibacterium spp.) and α-Proteobacteria (e.g.
Hyphomicrobium spp.) possibly involved in the nitrogen cycle. Cell numbers were
determined using a PCR-independent molecular detection method (CARD-FISH) with
universal 16S rRNA-specific probes (EUB338, ARCH915). The fraction of bacterial cells
comprised up to 104 cells per milliliter, which corresponds to the cell numbers obtained with
a generic DNA stain (DAPI). Archaeal cells could not be detected by CARD-FISH,
though archaeal 16S rRNA gene fragments were amplified from DNA extracts using
PCR.
So far differences have neither been observed between treated and untreated formation
waters nor between well head and in situ sampled formation waters.
Further investigations are underway to elucidate whether particular metabolic
pathways are present in the microbial assemblage of the Altmark gas field fluids. In
addition, microbe-mineral interactions will be assessed using electron microscopic
approaches.
Ehinger, S., Kassahun, A., Muschlle, T., Gniese, C., Schlömann, M., Hoth, N., Seifert, J.
(2009 submitted) Sulfate reduction by novel Thermoanaerobacteriaceae in bioreactor
inoculated with gas-field brine. Environmental Microbiology |
|
|
|
|
|
|