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Spatial realignment

Unless two surveys have been shot with the aim of reservoir monitoring, it is likely that they will have significantly different geometry; and unless they have been processed for reservoir monitoring, they may also be binned very differently.

The left side of Figure [*] shows the areal coverage of the two Gulf of Mexico datasets, and their 34$^\circ$ difference in azimuth. The 1979 survey covers a larger area, but there is a significant overlap.

 
geometries
geometries
Figure 2
Post-stack geometries. Left panel: the spatial coverage of the 1979 survey (dashed-line), and the 1991 survey (solid-line). Right panel: close-up of the different bin-spacings between the 1991 (denser) and 1979 (less dense) surveys.
view

The right side of Figure [*] shows a close-up of the bin-centers in part of the survey. The 1979 survey was shot and processed with bin-spacings of 82.5 ft (in-line), and 247 ft (cross-line); whereas the 1991 survey has 41 ft bin spacings in both the in-line and cross-line directions.

To compare the two surveys, the first step is to realign them both onto a common grid. In this case, we applied a spatial anti-aliasing filter in the (kx,ky) domain, and regridded the 1991 survey onto the 1979 grid. Since the 1991 survey was spatially-sampled so much more finely than the 1979 survey, a linear interpolation algorithm was used for the regridding, without causing artifacts.


next up previous print clean
Next: Matched-filtering Up: Rickett, et al.: STANFORD Previous: Gulf of Mexico example
Stanford Exploration Project
7/5/1998