Moving source profile data processing, modelling and comparison with 3D surface seismic data at the CO2SINK project site, Ketzin, Germany

Abstract

Baseline moving source profiling data were acquired in borehole Ketzin 202/2007 along seven lines at the Ketzin CO2 injection site in 2007. The data were recorded on eight three-component receivers spaced 10 m apart over a depth interval of 470-540 m. The main objective of the moving source profile survey was to generate high-resolution seismic images around the borehole. This was especially important given that the 3D surface seismic data in the area have a low fold at the injection site. Mapping of the sandy layers in the target formation (Stuttgart Formation) at around 630 m, the approximate CO2 injection depth, was another objective of the research. A comparison with repeat moving source profile surveys, during and after the injection, will be done in the future. A processing sequence consisting in hodogram analysis, wavefield separation and prestack migration was applied to the moving source profile data. A median filter was used to separate the downgoing and upgoing wave modes. The data were processed to generate depth migrated images in the vicinity of the borehole that could be compared with the 3D surface seismic data. Both the modelling studies that were carried out and the migrated images, indicate that the sandy layers within the Stuttgart Formation can potentially be imaged in the moving source profile data whereas reflections from these layers are not as clearly observed in the 3D surface seismic data. © 2010 European Association of Geoscientists & Engineers.