Prestack time migration from rugged surface topography

Abstract

Conventional migration techniques are based on the hypothesis of horizontal earth surface whereas the real receiving surface is generally non‐horizontal. Therefore static correction processing is needed to meet the requirement of migration schemes. Difference of statics may become significantly large when difference of height is large (like in the mountainous areas in southern and western China). Even if floating datum is adopted in migration processing, the imaging positions may still deviate noticeably from the real positions of reflection points, thus complex structures fail to migrate to its correct spatial positions. To cope with this problem, the author proposes to perform prestack time migration from rugged surface topography. The approach is made up of velocity analysis and model building, traveltime computation from rugged topography, and amplitude processing. The proposed approach has been tested on model data and has been successfully applied in the processing of real seismic data from southern China.