EFFICIENT 3-D MIGRATION IN TWO STEPS* |
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| Authors: | B GIBSON K LARNER S LEVIN |
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| Institution: | 1. Western Geophysical Co., POB 2469, Houston, Texas 77252, USA.;2. Currently at Stanford University, Department of Geophysics, Stanford, California 94305, U.S.A. |
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| Abstract: | The addition of a third dimension to seismic data acquisition offers significant improvement of our reflection images of geologic structures, but potentially at a substantial increase in data processing cost. Here we study an approach to migration of three-dimensional (3-D) stacked data that can considerably reduce the burden of computation and data manipulation. Cascading two-dimensional (2-D) migrations in orthogonal lateral directions, we obtain an efficient 3-D scheme that is exact for homogeneous media. As applied to examples of synthetic data from inhomogeneous media, the scheme introduces errors well below those attributable, in practice, to uncertainties in migration velocity. Application of this two-step approach, using both Kirchhoff-summation and finite-difference algorithms, to a 3-D seismic land survey over an area of known hydrocarbon traps additionally proves the importance of 3-D migration in stratigraphic imaging. |
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