Abstract: Complex structure imaging has become bottleneck of piedmont seismic exploration. Conventional seismic imaging method couldn't get correct imaging because of the limit of its algorithm and adaptability. This paper selects and analyzes the advantage of floating datum prestack depth migration over the mixed datum migration. By means of Kirchhoff integral method and wave equation method, it is shown that Kirchhoff integral method is more suitable for piedmont prestack migration. The correlation and analysis of the migration effect 2-D survey lines of piedmont zone indicate the effectiveness of this floating datum prestack depth migration method applied to piedmont complex structure imaging.

Key words: floating datum, prestack depth migration, piedmont zone, Kirchhoff integral method, migration aperture