多参考速度自适应横向变速深度延拓算子探讨

基于傅里叶变换法偏移算子,利用速度构造对速度场进行分区,探讨提高裂步傅里叶偏移法成像精度的方法.按速度分区的裂步傅里叶偏移方法一般把速度场分成了高速区和低速区,这不能适用于强横向变速介质.采取多参考速度的裂步傅里叶偏移方法可适应任意强横向变速介质,并且采用自适应的速度选取方式能提高成像精度.算法测试结果表明,多参考速度的参考速度选择方法是合理和稳定的,能够运用于复杂构造区的叠前或者叠后深度偏移成像.

Self-adaptive lateral velocity variation depth extrapolator based on multi-reference velocity selection

The velocity field was divided into several areas according to the differences of velocity field to improve the imaging precision by split-step Fourier (SSF) operator. The traditional split-step Fourier migration based on two velocity fields of higher-velocity part and lower-velocity part cannot deal with strong lateral velocity variation. The multi-reference velocity in SSF operator can adapt to arbitrary lateral velocity variation in a way of self-adaptive selection. Thus the imaging precision is considerably improved. The test results show that the method of multi-reference velocity is reasonable and steady, and can be used to pre-stack or post-stack depth migration imaging in complex structure area.