波动方程共方位角三维叠前偏移方法

本文针对双平方根(DSR)单程波动方程全三维偏移方法在地震波成像实际应用中面临的计算量大,对覆盖次数很低的窄方位三维地震资料会产生很强的相干噪声,影响成像效果等难题,结合Crossline共炮检距偏移理论,首先推导出了基于双域传播算子的共方位角叠前深度偏移公式,然后通过坐标变换提出了沿双程垂直走时方向进行递归波场延拓的共方位角叠前偏移新方法。通过对SEG/EAGE盐丘模型合成数据偏移试验,证实了共方位角叠前偏移深度域和时间域成像方法的有效性。将该法和常用的Kirchhoff叠前偏移法同时用于实际地震资料偏移处理对比,展示出该法在成像精度与分辨率方面具有明显的优势。

3-D wave equation common azimuth prestack migration

Facing the difficulties that the full 3-D migration by double squire root (DSR) one-way wave equation has large computational effort, strong coherent noise produced by narrow azimuth 3-D seismic data with low folds, affecting imaging effects when using this method for seismic imaging practice, the paper, combining with the crossline common offset migration theory, firstly deduced the common azimuth prestack depth migration formula based on propagation operator in double domain, then, presented a new method of common azimuth prestack migration that carries out recursive wavefield continuation along the direction of two-way vertical travel time by coordinate tranformation. It has been proved the effectiveness of the imaging method of common azimuth prestack migration in depth and time domains with the aid of migration test of synthetic data of SEG/EAGE salt dome model. Comparing with the common-used Kirchhoff prestack migration, the method showed distinctive advantages in imaging precision and resolution when processing same practical seismic data.