ISSN:
1365-2478
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Geosciences
,
Physics
Notes:
A three-dimensional (3-D) kinematic migration algorithm for media in which migration velocity varies linearly with depth is developed, implemented and tested. The algorithm is based on the concept that a single reflection or diffraction in a (zero- or finite-offset) trace may have originated at any point on a constant traveltime surface within the Earth defined by the observed two-way traveltime. The envelope of all such constant time surfaces, for all observed reflections and diffractions produced by one reflector, is the desired migrated 3-D image. The optimal envelope position in depth is determined, beneath each point on a regular grid, by a statistical imaging condition; an incremental function of depth containing the number of constant time surfaces passing through that depth increment is cross-correlated with a Gaussian function whose width is chosen to correspond to the vertical scale of the features of interest.The numerical procedures are based on the observation that, in a medium in which velocity varies linearly with depth, ray segments are circular so traveltimes can be computed analytically. Also, traveltimes are independent of azimuth so the 3-D problem can be collapsed into an equivalent 2-D problem.The algorithm is illustrated and tested by application to synthetic data and to scale-model data from the Seismic Acoustics Laboratory at the University of Houston.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2478.1987.tb00816.x
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