HR: 0830h
AN: NS51A-02 [Abstracts]
TI: High Resolution Near Surface 3D Seismic Experiments: A Carbonate Platform vs. a Siliciclastic Sequence
AU: * Filippidou, N
EM: n.filippidou@citg.tudelft.nl
AF: Delft University of Technology
Department of Applied Earth Sciences, PO BOX 5028, Delft, 2600GA Netherlands
AU: Drijkoningen, G
EM: g.g.drijkoningen@citg.tudelft.nl
AF: Delft University of Technology
Department of Applied Earth Sciences, PO BOX 5028, Delft, 2600GA Netherlands
AU: Braaksma, H
EM: brah@geo.vu.nl
AF: Vrije Universiteit
Department of Earth & Life Sciences, de Boelelaan 10855, Amsterdam, 1081 Netherlands
AU: Verwer, K
EM: klaas.verwer@falw.vu.nl
AF: Vrije Universiteit
Department of Earth & Life Sciences, de Boelelaan 10855, Amsterdam, 1081 Netherlands
AU: Kenter, J
EM: jeroen.kenter@falw.vu.nl
AF: Vrije Universiteit
Department of Earth & Life Sciences, de Boelelaan 10855, Amsterdam, 1081 Netherlands
AB:
Interest in high-resolution 3D seismic experiments for imaging shallow targets has increased over the past years. Many case
studies presented, show that producing clear seismic images with this non-evasive method, is still a challenge.
We use two test-sites where nearby outcrops are present so that an accurate geological model can be built and the seismic
result validated. The first so-called natural field laboratory is located in Boulonnais (N. France). It is an upper Jurassic
siliciclastic sequence; age equivalent of the source rock of N. Sea. The second one is located in Cap Blanc,to the southwest
of the Mallorca island(Spain); depicting an excellent example of Miocene prograding reef platform (Llucmajor Platform); it is a textbook analog for carbonate reservoirs. In both cases, the multidisciplinary experiment included the use of
multicomponent and quasi- or 3D seismic recordings. The target depth does not exceed 120m. Vertical and shear portable
vibrators were used as source. In the center of the setups, boreholes were drilled and Vertical Seismic Profiles were shot,
along with core and borehole measurements both in situ and in the laboratory. These two geologically different sites, with
different seismic stratigraphy have provided us with exceptionally high resolution seismic images. In general seismic data
was processed more or less following standard procedures, a few innovative techniques on the Mallorca data, as rotation of
horizontal components, 3D F-K filter and addition of parallel profiles, have improved the seismic image.
In this paper we discuss the basic differences as seen on the seismic sections. The Boulonnais data present highly continuous reflection patterns of extremenly high resolution. This facilitated a high resolution stratigraphic description. Results
from the VSP showed substantial wave energy attenuation. However, the high-fold (330 traces ) Mallorca seismic experiment
returned a rather discontinuous pattern of possible reflectors, opposing to the predicted seismic stratigraphy/geology of the area. The Llumajor Platform has been buried only a few meters at most, therefore primary and secondary porocity remains
intact, creating a fractal like environment of scatterers and diffractors. We have interpreted two possible reflections, the
top of the reef and the water table; the former is nicely coupled with the VSP. The seismic wave attenuation observed is
believed to be predominantly due to the scattering effects.
DE: 0910 Data processing
DE: 0935 Seismic methods (3025)
DE: 4275 Remote sensing and electromagnetic processes (0689)
DE: 5144 Wave attenuation
DE: 7203 Body wave propagation
SC: Near-Surface Geophysics [NS]
MN: 2005 Joint Assembly