New insights into vintage 3D reflection seismic data in hard-rock environment

The demand for reliable high-resolution reflection seismic exploration campaign in hard-rock environments increases continuously. The target of such surveys varies and covers e.g. mineral exploration, geothermal reservoir characterization or the exploration of potential nuclear waste deposit sites. Although the exploration targets are very different, the expectations on the seismic images and the challenges for data acquisition and processing are similar. The expected structures are often steeply dipping with varying strike directions and conflicting dip situations. Furthermore, the reflection seismic data often has to be acquired on land, possibly in populated areas, or in areas with severe accessibility restrictions. These limitations lead to irregular or sparse datasets in combination with sometimes low signal-to-noise ratio for the target reflections in the recorded data.

 

Therefore, robust imaging methods are needed to generate high resolution reflection seismic images for such kind of data. Focusing prestack depth migration methods have proven to deliver improved image quality compared to standard time- or depth migration approaches. We show the results of our focusing pre-stack depth migration techniques applied to a vintage 3D seismic data set (ISO89) acquired in 1989 around the German deep continental drill site (KTB). We show a comparison to other previously obtained seismic images for the same data set and how the image quality evolved over time.