Development of a system for 3D high-resolution seismic reflection profiling on lakes
| Autor: | M. Scheidhauer, D. Dupuy, François Marillier |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2005 |
| Předmět: |
geography
geography.geographical_feature_category 3D air gun high-resolution Lake Geneva Molasse multi-channel navigation reflection seismics seismic acquisition Switzerland business.industry Fault (geology) Oceanography Signal Bin Geophysics Sampling (signal processing) Geochemistry and Petrology Offshore geotechnical engineering Global Positioning System Reflection (physics) Differential GPS business Seismology Geology |
| Zdroj: | Marine Geophysical Researches, vol. 26, pp. 183-195 |
| Popis: | A high-resolution three-dimensional (3D) seismic reflection system for small-scale targets in lacustrine settings has been developed. Its main characteristics include navigation and shot-triggering software that fires the seismic source at regular distance intervals (max. error of 0.25 m) with real-time control on navigation using differential GPS (Global Positioning System). Receiver positions are accurately calculated (error < 0.20 m) with the aid of GPS antennas attached to the end of each of three 24-channel streamers. Two telescopic booms hold the streamers at a distance of 7.5 m from each other. With a receiver spacing of 2.5 m, the bin dimension is 1.25 m in inline and 3.75 m in crossline direction. To test the system, we conducted a 3D survey of about 1 km(2) in Lake Geneva, Switzerland, over a complex fault zone. A 5-m shot spacing resulted in a nominal fold of 6. A double-chamber bubble-cancelling 15/15 in(3) air gun (40-650 Hz) operated at 80 bars and 1 m depth gave a signal penetration of 300 m below water bottom and a best vertical resolution of 1.1 m. Processing followed a conventional scheme, but had to be adapted to the high sampling rates, and our unconventional navigation data needed conversion to industry standards. The high-quality data enabled us to construct maps of seismic horizons and fault surfaces in three dimensions. The system proves to be well adapted to investigate complex structures by providing non-aliased images of reflectors with dips up to 30 degrees. |
| Databáze: | OpenAIRE |
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