We present a new migration method which utilizes the Gaussian beam approach. The method, though based on a high frequency approximation, operates on whole time sections and not merely on selected digitized horizons as in ray tracing map migration. However the method maintains many of the advantages of ray tracing such as the ability to migrate only certain propagation angles or to focus on selected regions without having to downward continue beneath the whole area of the survey. In order to affect Gaussian beam migration, the recorded time section is first temporally transformed from the x - t domain into the x-w domain. The data is then beam stacked by the Gabor expansion (Raz, 1987). The stacking can be carried out over receiver coordinates, or over both receiver and shot coordinates. The expansion coefficients give amplitudes of Gaussian beams where each coefficient corresponds to a specific beam origin and beam angle. Each beam is then downward continued into the subsurface. The final migrated section consists of a sum of amplitude contributions from all beams at all frequencies. Beam migration can be carried out on both CMP stacked sections as well as on prestacked data. For the latter, as in conventional prestack migration there is a possibility of migrating all shots separately or of downward continuing both shots and receivers. Beam migration is demonstrated on a number of synthetic examples as well as on stacked field data. The results indicate that this migration is of high quality and offers a number of advantages over existing techniques.
|Number of pages||3|
|State||Published - 1989|
|Event||1989 Society of Exploration Geophysicists Annual Meeting, SEG 1989 - Dallas, United States|
Duration: 29 Oct 1989 → 2 Nov 1989
|Conference||1989 Society of Exploration Geophysicists Annual Meeting, SEG 1989|
|Period||29/10/89 → 2/11/89|