Affiliation:
1. Stanford Exploration Project, Geophysics Dept., 360 Mitchell Bldg., Stanford, California 94305-2215
Abstract
We introduce a new partial prestack‐migration operator called “azimuth moveout” (AMO) that rotates the azimuth and modifies the offset of 3-D prestack data. Followed by partial stacking, AMO can reduce the computational cost of 3-D prestack imaging. We have successfully applied AMO to the partial stacking of a 3-D marine data set over a range of offsets and azimuths. When AMO is included in the partial‐stacking procedure, high‐frequency steeply dipping energy is better preserved than when conventional partial‐stacking methodologies are used. Because the test data set requires 3-D prestack depth migration to handle strong lateral variations in velocity, the results of our tests support the applicability of AMO to prestack depth‐imaging problems. AMO is a partial prestack‐migration operator defined by chaining a 3-D prestack imaging operator with a 3-D prestack modeling operator. The analytical expression for the AMO impulse response is derived by chaining constant‐velocity DMO with its inverse. Equivalently, it can be derived by chaining constant‐velocity prestack migration and modeling. Because 3-D prestack data are typically irregularly sampled in the surface coordinates, AMO is naturally applied as an integral operator in the time‐space domain. The AMO impulse response is a skewed saddle surface in the time‐midpoint space. Its shape depends on the amount of azimuth rotation and offset continuation to be applied to the data. The shape of the AMO saddle is velocity independent, whereas its spatial aperture is dependent on the minimum velocity. When the azimuth rotation is small (⩽20°), the AMO impulse response is compact, and its application as an integral operator is inexpensive. Implementing AMO as an integral operator is not straightforward because the AMO saddle may have a strong curvature when it is expressed in the midpoint coordinates. An appropriate transformation of the midpoint axes to regularize the AMO saddle leads to an effective implementation.
Publisher
Society of Exploration Geophysicists
Subject
Geochemistry and Petrology,Geophysics
Reference32 articles.
1. Bagaini, C., Spagnolini, U., and Pazienza, V., 1994, Velocity analysis and missing offset restoration by prestack continuation operators: 65th Ann. Internat. Mtg., Soc. Expl. Geophys., Expanded Abstracts, 1549–1552.
2. Bevc, D., and Claerbout, J., 1992, Fast anti‐aliased Kirchhoff migration and modeling: Stanford Expl. Proj.75, 91–96.
3. Imaging of discontinuities in the inverse scattering problem by inversion of a causal generalized Radon transform
4. Biondi, B., and Chemingui, N., 1994, Transformation of 3-D prestack data by azimuth moveout (AMO): 65th Ann. Internat. Mtg., Soc. Expl. Geophys., Expanded Abstracts, 1541–1544.
5. 3-D prestack migration of common‐azimuth data
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