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- Volume 6, Issue 8, 1988
First Break - Volume 6, Issue 8, 1988
Volume 6, Issue 8, 1988
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Directional deconvolution of the seismic source signature combined with prestack migration
Authors G.A. Roberts and N.R. GoultyModern marine seismic source arrays are highly directional. The directivity of the far-field source signature is ignored in conventional one-dimensional (lD) deconvolution. For a single seismic reflection profile it is assumed that all arrivals arise from raypaths lying in the in-line plane, and so some kind of two-dimensional (2D) deconvolution operator is required to remove the directivity of the source signature. This may be achieved in combination with prestack migration. Conceptually, the prestack migration is done by taking each data sample on a constant-offset section and smearing it along a locus on the migrated section. This locus is an ellipse for constant velocity. There is a one-for-one correspondence between points on the migration ellipse and the take-off angle of the waveform radiated from the source. So the constant-offset section may be deconvolved before migration for the source waveforms radiated in different directions, and the output values distributed at the appropriate points on the migration ellipses. Suitable weighting factors may be chosen for the migration process, and a spectral modification factor should be applied. Directional deconvolution of the seismie source signature could also be implemented in combination with dip moveout (prestack partial migration of constant offset sections to zero offset) and could be extended to three-dimensional (3D) data and to incorporate receiver directivity. We illustrate the technique using 2D data from a physical modelling system.
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Flexichoc FHC50 seismic source
By K.P. GamesA comprehensive account of the Flexichoc FHC 50 seismic source is presented in terms of the way in which the source works, its pulse shape and frequency content, and the logistical considerations concerning deployment and operation. Data examples acquired during normal operations illustrate that this source is ideal for high-resolution digital seismic acquisition, giving resolution to within 2 m of the seabed, and allowing penetration to 2 s TWT. This paper also compares the manufacturer's supplied characteristics with field trials, and includes a direct comparison between adjacent survey lines with the Flexichoc and a sparker source.
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Volume 42 (2024)
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Volume 19 (2001)
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Volume 17 (1999)
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Volume 16 (1998)
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Volume 15 (1997)
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Volume 14 (1996)
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Volume 13 (1995)
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Volume 12 (1994)
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Volume 11 (1993)
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Volume 10 (1992)
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Volume 9 (1991)
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Volume 8 (1990)
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Volume 7 (1989)
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Volume 6 (1988)
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Volume 5 (1987)
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Volume 4 (1986)
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Volume 3 (1985)
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Volume 2 (1984)
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Volume 1 (1983)