Wide-azimuth 3D angle gathers based on wave equation migration
CHEN Fei-Xu1, LI Zhen-Chun1, ZHANG Kai1, SUN Qi2, SHANG Jiang-Wei2
1. School of Geosciences, China University of Petroleum(East China), Qingdao 266580, China;
2. Research Institution of Petroleum Exploration and Development, Tarim Oilfield, PetroChina, Korla 841000, China
Wide-azimuth angle gathers based on 3D wave equation migration contain not only the information of local reflection angle but also that of subsurface azimuth angle.It fully reflects the illumination of the target from different azimuths under the wide-azimuth acquisition,which makes itself important in 3D migration velocity analysis in complex structure.Starting with the viewpoint of angle decomposition,this paper discussed the relationship of ray parameter,reflection angle and local azimuth angle,implemented the mapping of the local offset-domain common image gather to the angle-domain common image gather,and gave the work flow of the method.Synthetic model tests and field data application demonstrate that the angle gathers extracted with the proposed method can truly reflect the reflection information from different azimuths in the subsurface,provide gather basis for 3D seismic pre-stack depth migration, and thus can be used to analyze amplitude versus angle in 3D.
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