省时2D叠前深度偏移

利用从地震剖面得到的倾角信息估算入射波方向，可以大幅度提高Kirchhoff偏移的计算效率。省时2D Kirchhoff叠前深度偏移方法通过对常规方法两方面的改进，提高了计算效率：1）以计算的射线参数或倾角参数作为先验信息，这样可以大大减少射线追踪的时间；2）通过一个设定的振幅门槛值对输入地震数据作压缩，进而减少总的计算时间。与常规的Kirchhoff偏移方法相比，该方法不需要建立旅行时表，因此它需要相对较小的内存和磁盘空间，以及I／O时间。合成理论数据测试表明，该算法计算效率明显提高。

Parsimonious 2-D pre-stack depth migration

Computational efficiency of Kirchhoff migration can be improved drastically by using slope information from seismic section to estimate the incident wave direction. Two aspects of conventional migration methods are improved by parsimonious 2 D Kirchhoff pre stack depth migration. The computational ray and dip parameters are used as prior information that results in great reduction of ray tracing time. Data are compressed by setting an amplitude threshold value that results in decrement of overall computation time. Comparing with conventional Kirchhoff migration methods, this method have no need for construction of travel time table, therefore it demands relatively lesser memory and disk space, and I/O time as well. Synthetic data tests show that this algorithm is much faster than the conventional Kirchhoff migration methods.