双方位地震资料联合成像处理技术在深水崎岖海底区的应用

Two-azimuth deepwater seismic data combined imaging in rugged seabed areas

南海北部陆坡区崎岖海底发育,水深变化剧烈,中深层地质条件复杂,常规的窄方位三维地震采集数据难以满足陆坡变水深条件下的地震成像和目标评价的需要。针对琼东南盆地宝岛凹陷崎岖海底区采集的双方位地震资料,分析了不同采集方位角三维地震资料的差异,采用双方位联合速度建模以及双方位各向异性深度偏移联合成像,提高了速度建模精度,并实现了双方位三维地震资料的融合处理。实际地震资料处理结果表明,双方位融合成像的同相轴更加连续、稳定,较好解决了崎岖海底下伏地层的成像问题,提高了复杂构造区的成像精度,为后续构造解释及进一步目标综合研究提供了可靠依据。

Because of water-depth rapid changes in rough deep sea bottoms and complex geological structures of mid-deep layers in the north of South China Sea,narrow-azimuth 3D seismic imaging cannot meet requirements of the target evaluation.Therefore two-azimuth 3D seismic data acquisitions are conducted in the Baodao Sag,the Qiongdongnan Basin.First we analyze differences of migration velocity and anisotropic parameters in different azimuths on these data sets.Then we build velocity models of two-azimuth 3D seismic data with tomographic inversion.Finally we achieve prestack depth migration combined imaging with two-azimuth anisotropic velocity model.Seismic data examples in this area show that the proposed approach obtains more continuous and stable events and achieve better imaging of complex structures,which are helpful for the structural interpretation and the target evaluation.