Introduction

Multicomponent seismic data may hold a wealth of information for oil exploration and reservoir characterization. Multicomponent seismic contains energy from converted waves that is not seen in conventional seismic; therefore, the development of new techniques to process converted-wave data is important. Much progress has been made in many areas of converted-wave seismic processing, such as stacking, DMO, migration and velocity analysis Alfaraj (1992); Harrison and Stewart (1993); Huub Den Rooijen (1991); Iverson et al. (1989); Tessmer and Behle (1988). However, more advanced techniques for single-mode PP seismic still have few converted-wave counterparts.

Common-azimuth migration is an efficient and robust technique for obtaining accurate single-mode PP 3-D seismic images. This technique takes advantage of the reduced dimensionality of the computational domain. It assumes that the data have only the zero cross-line offset; that is, all the traces in the data share the same azimuth Biondi and Palacharla (1996). Due to the growing number of 3-D multicomponent seismic data sets in areas where an accurate processing is required to obtain better subsurface images and/or estimate rock properties, wavefield-based continuation methods, such as common-azimuth migration, for converted-mode data are of great importance and are very much needed in the oil industry today.

Converted-wave common-azimuth migration is very similar to conventional common-azimuth migration. However, it uses different propagation velocities for different wavefields. We compare the differences between single-mode and converted-mode common-azimuth migration.