ausblenden:
Schlagwörter:
CO2 storage;
Ketzin CO2 pilot storage site
Zusammenfassung:
A case study for the combination of geoelectric
and seismic processing by means of a structurally
constrained inversion approach is presented. Structural constraints are interpreted from the seismic data and integrated into the geoelectric inversion through a local regularization which allows inverted resistivities to behave discontinuously across defined boundaries. This arranges seismic processing and constrained resistivity inversion in a sequential workflow, making the generic assumption that the petrophysical parameters of relevant to each method change across common lithostructural boundaries.
The approach is evaluated using both a numerical example and a real data example from the Ketzin CO2 pilot storage site, Germany. The latter demonstrates the efficiency of this approach for combining 4D seismic and surface-downhole geoelectric data. In consistence with the synthetic
example, the constrained resistivity inversions of the real data produce clearer delineated images along the boundary between the caprock and the CO2 storage reservoir. Near the CO2 flooded reservoir, the seismic and geoelectric time lapse anomalies correlate well. At some distance to the
downhole electrodes, however, the geoelectric images convey a notably lower resolution in comparison to the corresponding seismic images. Although a northerly direction for the CO2 migration was initially expected, both methods confirm a rather northwesterly migration trend.
The results confirm the relevance of the presented approach for the combination of both methods for geophysical CO2
storage monitoring.
