Dip-domain migration of two-dimensional seismic profiles
Two-dimensional migration of seismic time sections by a digital computer has been performed by a variety of techniques, ranging from computer-simulated hand migration to a computer simulation of elastic wave propagation from the surface receiver positions back into the subsurface. Past processes have utilized the normal moveout equation, whereas the subject process is an application of its spatial derivative. Dip-domain migration pertains to special sections where all events have the same space-time slope, and the migration at each slope is approximated by a trivial function of the subsurface rms velocity and the associated vertical two-way traveltime. The actual process is to dip decompose a seismic section into so-called dip blocks through the applications of appropriate dip-discriminating coherency functions, migrate the individual dip blocks, and recompose the migrated dip components (dip blocks). The dip-discriminating coherency functions are computed from a combination of an algebraic and an absolute dipping spatial mix of the seismic time section. The input seismic data are not themselves spatially mixed on the dip blocks, but, rather, they are reduced in amplitude by the coherency functions for the dip blocks of which they are not a coherent component. Migration formulas are developed for both spatially invariant and variable subsurface velocity functions. The subject process has some computational advantages. In addition, improved signal-to-noise ratios are consistently obtained due to the dip bandpass (fan) filtering inherent to the process. Synthetic and field seismic examples are included. 14 figures.
- Research Organization:
- Cities Service Oil Co., Tulsa OK
- OSTI ID:
- 5728103
- Journal Information:
- Geophysics; (United States), Vol. 43:1
- Country of Publication:
- United States
- Language:
- English
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