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| Titel |
Surface-downhole and crosshole geoelectrics for monitoring of brine injection at the Ketzin CO2 storage site |
| VerfasserIn |
Dennis Rippe, Peter Bergmann, Tim Labitzke, Florian Wagner, Cornelia Schmidt-Hattenberger |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250134644
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| Publikation (Nr.) |
 EGU/EGU2016-15388.pdf |
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| Zusammenfassung |
| The Ketzin pilot site in Germany is the longest operating on-shore CO2 storage site in
Europe. From June 2008 till August 2013, a total of ∼67,000 tonnes of CO2 were safely
stored in a saline aquifer at depths of 630 m to 650 m. The storage site has now entered the
abandonment phase, and continuation of the multi-disciplinary monitoring as part of the
national project "CO2 post-injection monitoring and post-closure phase at the Ketzin pilot
site" (COMPLETE) provides the unique chance to participate in the conclusion of the
complete life cycle of a CO2 storage site.
As part of the continuous evaluation of the functionality and integrity of the CO2 storage
in Ketzin, from October 12, 2015 till January 6, 2015 a total of ∼2,900 tonnes of brine were
successfully injected into the CO2 reservoir, hereby simulating in time-lapse the natural
backflow of brine and the associated displacement of CO2. The main objectives of this brine
injection experiment include investigation of how much of the CO2 in the pore
space can be displaced by brine and if this displacement of CO2 during the brine
injection differs from the displacement of formation fluid during the initial CO2
injection.
Geophysical monitoring of the brine injection included continuous geoelectric
measurements accompanied by monitoring of pressure and temperature conditions in the
injection well and two adjacent observation wells. During the previous CO2 injection, the
geoelectrical monitoring concept at the Ketzin pilot site consisted of permanent
crosshole measurements and non-permanent large-scale surveys (Kiessling et al.,
2010). Time-lapse geoelectrical tomographies derived from the weekly crosshole
data at near-wellbore scale complemented by six surface-downhole surveys at a
scale of 1.5 km showed a noticeable resistivity signature within the target storage
zone, which was attributed to the CO2 plume (Schmidt-Hattenberger et al., 2011)
and interpreted in terms of relative CO2 and brine saturations (Bergmann et al.,
2012).
During the brine injection, usage of a new data acquisition unit allowed the
daily collection of an extended crosshole data set. This data set was complemented
by an alternative surface-downhole acquisition geometry, which for the first time
allowed for regular current injections from three permanent surface electrodes into the
existing electrical resistivity downhole array without the demand of an extensive field
survey. This alternative surface-downhole acquisition geometry is expected to be
characterized by good data quality and well confined sensitivity to the target storage
zone.
Time-lapse geoelectrical tomographies have been derived from both surface-downhole
and crosshole data and show a conductive signature around the injection well associated with
the displacement of CO2 by the injected brine. In addition to the above mentioned objectives
of this brine injection experiment, comparative analysis of the surface-downhole and
crosshole data provides the opportunity to evaluate the alternative surface-downhole
acquisition geometry with respect to its resolution within the target storage zone and its
ability to quantitatively constrain the displacement of CO2 during the brine injection. These
results will allow for further improvement of the deployed alternative surface-downhole
acquisition geometries.
References
Bergmann, P., Schmidt-Hattenberger, C., Kiessling, D., Rücker, C., Labitzke, T., Henninges, J., Baumann, G.,
Schütt, H. (2012). Surface-Downhole Electrical Resistivity Tomography applied to Monitoring of the CO2 Storage
Ketzin (Germany). Geophysics, 77, B253-B267.
Kiessling, D., Schmidt-Hattenberger, C., Schuett, H., Schilling, F., Krueger, K., Schoebel, B., Danckwardt, E.,
Kummerow, J., CO2SINK Group (2010). Geoelectrical methods for monitoring geological CO2 storage: First results
from cross-hole and surface-downhole measurements from the CO2SINK test site at Ketzin (Germany).
International Journal of Greenhouse Gas Control, 4(5), 816-826.
Schmidt-Hattenberger, C., Bergmann, P., Kießling, D., Krüger, K., Rücker, C., Schütt, H., Ketzin Group (2011).
Application of a Vertical Electrical Resistivity Array (VERA) for monitoring CO2 migration at the Ketzin site: First
performance evaluation. Energy Procedia, 4, 3363-3370. |
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