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| Titel |
Biogeochemical and microbial analyses around gas wells and in the reservoir in a long-term used gas field |
| VerfasserIn |
Dagmar Kock, Martin Krüger |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250033422
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| Zusammenfassung |
| As part of a joint research project microbial communities in the area of the second largest
natural gas field in Europe in the Altmark, Germany are analyzed. The Altmark
gas field operated by GDF SUEZ E&P Germany GmbH is located at the southern
edge of the Northeast German Basin. The reservoir horizons belong to the Permian
Rotliegend formation (Saxon) and have an average depth of about 3300 m. CO2
will be injected to enhance the recovery of gas in this with conventional extraction
methods nearly depleted gas field (Enhanced Gas Recovery – EGR, BMBF project
CLEAN).
Microbiological analyses are used to supplement a continuous gas monitoring program at
the soil surface above the EGR-site. Microbial production and consumption of CH4 and CO2
are determined together with the carbon isotopic compositions to separate these indigenous
biological activities from possibly upward migrating reservoir gases including CO2. The
δ13C of CO2 collected in situ was similar to those in incubations, confirming a
biological origin. Archaeal cell numbers were approximately one magnitude lower than
bacterial cell numbers. In all samples the total number of detectable microorganisms
was high in contrast to a generally low activity for CO2 and CH4 production and
oxidation.
For monitoring of the deep reservoir microbiological and isotopic analyses are used to
investigate the microbial community before and after injection of CO2. The δ13C of CO2 and
CH4 collected in situ in production waters indicate a thermogenic origin. High cell numbers
for bacteria and archaea were detected in production waters from different wells. In contrast
microbial activities for CO2 and CH4 production and oxidation were relatively low. So far
microbial activities in reservoir fluids collected with in situ samplers at 3512m depth could
not be determined in this hypersaline (salinity of 400 per mille) and hot (around 130Ë C)
environment. |
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