Plane-wave migration for steep reflectors imaging

Abstract

The application of plane-wave migration for the steep reflectors imaging is investigated. Due to the limited aperture, a single common shot migration based on the one-way wave equation is not effective for the dipping structures imaging. Plane-wave migration, which can produce equal or higher quality images with much less computation cost than conventional shot migration, doesn?t suffer from the aperture problems of common-shot records since their recording aperture is the length of the seismic survey. We have found that the corresponding relation between the angle of dipping reflectors and the surface ray parameters P can be estimated from the initial velocity information. On one hand, we improve the wavefield extrapolation accuracy only for common P sections corresponding the selected steep targets, in which way, the imaging accuracy of the selected targets can be improved; on the other hand, the plane-wave integrals can be pruned to concentrate the image on the selected targets, in which way, the computation time can be further reduced. Synthetic left salt body dataset from the BP 2004 velocity benchmark and VTI synthetic dataset from Amerada Hess are used to demonstrate the methods respectively for the isotropic and anisotropic case. Then we extend it to real data of Luzong area in China for steep structures imaging. Synthetic and real data examples show that plane-wave migration generates high-quality images of steeply dipping reflectors with very low computation cost.