射线变速深度偏移

Ray depth migration in velocity varied medium.

以射线理论为基础的一步法深度偏移具有效率高,适应低信噪比资料的优点,但实现起来比较困难。笔者认为,实现一步法射线深度偏移的关键是正确解决射线速度的各向变化问题。在深度域利用介质速度计算各向变化的射线速度,并用实际绕射曲线替换传统双曲线型绕射曲线,即可获得令人满意的一步法射线深度偏移效果。

One-step depth migration based on ray theory is efficient and applicable to low S/N seismic data,but remains difficult to achieve.The authors think that the key to successful one-step ray depth migration is to well cope with ray velocity variation in all directions.Satisfactory one-step ray depth migration can be achieved by calculat ing variable ray velocity with the use of“medium velocity”in depth domain,and re- placing traditional hyperbolic diffraction curve with actual diffraction curve.