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Absorption related velocity dispersion below a possible gas hydrate geobody
Author(s) -
Jones Ian F.
Publication year - 2013
Publication title -
geophysical prospecting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.735
H-Index - 79
eISSN - 1365-2478
pISSN - 0016-8025
DOI - 10.1111/j.1365-2478.2012.01128.x
Subject(s) - geology , submarine pipeline , clathrate hydrate , dispersion (optics) , velocity dispersion , regional geology , mineralogy , bandwidth (computing) , wavelet , seismology , inversion (geology) , porosity , waveform , geophysics , hydrate , metamorphic petrology , optics , geotechnical engineering , chemistry , radar , tectonics , telecommunications , physics , organic chemistry , quantum mechanics , artificial intelligence , galaxy , computer science
Velocity dispersion is not usually a problem in surface seismic data processing, as the seismic bandwidth is relatively narrow and thus for most Q values, dispersive effects are not noticeable. However, for highly absorptive bodies, such as the overpressured free gas accumulations associated with some gas hydrates or high‐porosity normally pressured gas sands, dispersive effects may be seen. In this work I analyse one such data set from the offshore north‐east coast of India. I demonstrate that the effect is measurable and that compensating for it in either data processing or migration can improve the wavelet character, as well as delivering an estimate of the effective Q values in the associated geobody. I also raise the question as to whether velocities derived using low‐frequency waveform inversion over such dispersive geobodies are wholly appropriate for migration of full seismic‐bandwidth data.