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Phase‐shift migration with a variable‐length spatial transform–an algorithm for moderately varying lateral velocities 1
Author(s) -
Benson Alvin K.
Publication year - 1995
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.1365-2478.1995.tb00277.x
Subject(s) - position (finance) , algorithm , variable (mathematics) , recursion (computer science) , fast fourier transform , phase (matter) , geology , process (computing) , geometry , mathematics , physics , computer science , mathematical analysis , finance , quantum mechanics , economics , operating system
Abstract A migration algorithm appropriate for moderately varying lateral velocity changes is developed as an extension of phase‐shift migration by using a variable‐length spatial transform. This process significantly reduces the number of lateral wave‐numbers necessary to downward continue the data, and it replaces the spatial FFT with a simple recursion relationship. For a given frequency and position x , ten lateral wavenumbers are typically sufficient, and the migration algorithm produces accurate images when the velocity structure V ( X, z ) changes over a few depth intervals of thickness Δz, with lateral velocity gradients up to 1.4 to 1.0.