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f Prestack frequency-wavenumber (f-k) migration in a transversely isotropic medium
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 53rd EAEG Meeting, May 1991, cp-42-00041
- ISBN: 978-90-73781-03-0
Abstract
Prestack frequency-wavenumber (f-k) migration (Stolt, 1978) is an efficient way to do prestack time migration. This technique is also useful for migration velocity estimation, where it is expected to yield dipindependent velocities (Li et al, 1991). In practice, however, we often find that imaging velocities do exhibit dip-dependency. This is especially noticeable with fault-plane reflections which usually image best at velocities higher than those of surrounding flat events. In a companion paper (Lynn et al, 1991), it is shown that the dip dependency of migration velocities can be explained by assuming that waves have propagated in a transversely isotropic earth. Because anisotropy affects both processing and interpretation of seismic data, it is important to identify its presence and measure its strength. In this paper we develop the necessary modifications to prestack f-k migration that compensate for such media. Moreover, we find that the transverse-isotropy adjustment parameter can be used to estimate, in an average sense, the amount of transverse isotropy.