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| Titel |
Comparative 2D BRT and seismic modeling of CO2 plumes in deep saline reservoirs |
| VerfasserIn |
Said Attia al Hagrey, Matthias Strahser, Wolfgang Rabbel |
| 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 |
250035154
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| Zusammenfassung |
| The multi-disciplinary research project “CO2 MoPa” (modeling and parameterization of CO2
storage in deep saline formations for dimensions and risk analysis) deals, among others, with
the parameterization of virtual subsurface storage sites to characterize rock properties with
modeling of processes related to CCS in deep saline reservoirs. The geophysical task is to
estimate the sensitivity and the resolution of reflection seismic and geoelectrical time-lapses
in order to determine the propagation of CO2 within the sediments and the development of
the CO2 reservoir. Compared with seismic, borehole electric resistivity tomography (BRT)
has lower resolution, but its permanent installation and continuous monitoring can make it an
economical alternative or complement. Seismic and geoelectric applications to quantify
changes of intrinsic aquifer properties with time are justified by the lower density and
velocity and the higher electric resistivity of CO2 in comparison to pore brine.
We present here modeling results on scenarios with realistic parameters of deep
saline formations of the German Basin (candidate for CCS). The study focuses on
effects of parameters related to depth (temperature, pressure), petrophysics (salinity,
porosity), plume dimensions/saturations and data acquisition, processing and inversions.
Both methods show stronger effects with increasing brine salinity, CO2 reservoir
thickness, porosity and CO2 saturation in the pores. Both methods have a pronounced
depth dependence due to the pressure and temperature dependence of the velocities,
densities and resistivities of the host rock, brine and CO2. Increasing depth means
also decreasing frequencies of the seismic signal and hence weaker resolution.
Because of the expected limited thickness of the CO2 reservoir, the reflections from its
top and bottom will most likely interfere with each other, making it difficult to
determine the exact dimensions of the reservoir. In BRT, the resulting resistivity
resolution and anomaly magnitudes are inversely proportional to the host salinity and
temperatures and directly proportional to CO2 saturation and reservoir dimensions. The
sensitivity of the seismic method to changes in saturation is most pronounced for low
CO2 concentrations while the geoelectric method has a higher sensitivity at high
concentrations.
Acknowledgements:
This study is funded by the German Federal Ministry of Education and Research (BMBF),
EnBW Energie Baden-Württemberg AG, E.ON Energie AG, E.ON Ruhrgas AG, RWE Dea
AG, Vattenfall Europe Technology Research GmbH, Wintershall Holding AG and Stadtwerke
Kiel AG as part of the CO2-MoPa joint project in the framework of the Special Program
GEOTECHNOLOGIEN. |
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