Extended marine arrays versus simulated extended arrays
Journal name: Geophysical Prospecting
Issue: Vol 34, No 8, December 1986 pp. 1154 - 1166
Info: Article, PDF ( 587.93Kb )
Two factors are responsible for the fact that an extended marine source array performs better than a point source:
1. a higher degree of transmission of the radiated seismic energy through the water-sediment interface providing a better penetration;
2. filtering effects.
The higher degree of transmission is due to: (a) the directivity of extended sources, (b) the lower reflection coefficient at the water-sediment interface for seismic waves radiated from an extended source array than for spherical seismic waves radiated from a point source, (c) the lower amplitude decay of the pulses from an extended source than from a point source. In addition, signature characteristic of an extended source array and Fresnel zone of waves generated by such a source differ from those corresponding to a point source.
The propagating wavelet radiated from a point source array may not be, in a sedimentary sequence below the sea-floor, the linear combination of wavelets emitted from point sources. In such cases, there is a noticeable difference between the performance of a field-implemented source array and that of the corresponding simulated source array. The performances of the field-implemented and simulated extended receiver arrays can be identical if the recording system is adequate and the processing technique appropriate.