SU道集叠加 [chunshu]

 

   SU道集叠加有多种方式，主要用到的有直接叠加、差异叠加以及加权相位叠加等方法，所涉及的命令主要有：sustack, sudivstack, supws，用于水平叠加，近道直接叠加，叠前偏移的共成像点道集叠加等等。这里简单试验直接叠加和差异叠加。

  

数据，一个炮集，然后复制多个这样的炮集，并在数据上加入一定的随机噪声

普通叠加：sustack <data >odata

 

差异叠加(average power, 默认整个道长)：sudivstack <data >odata

差异叠加(average power, 加窗1s)：sudivstack <data winlen=1 >odata

差异叠加（peak power）：sudivstack <data peak=1 >odata

从叠加效果上看，差异叠加的效果明显好于普通叠加方法。 但是，各种叠加方法在不同的场合有不同的效果，需要多次测试进行选取。

 

注：

The diversity stacking technique has a major disadvantage as follows. The technique relies on the assumption that the noise component of each of the seismic traces is uncorrelated with the noise component in any of the other traces. However, in many practical situations, this assumption is not actually valid. It has been found that, as a result, diversity stacking can often result in rather poor signal-to-noise ratios. The correlation of noise components may be due to having originated at the same source (for example a factory) or, since the correlation is a mathematical concept, coincidentally from separate sources.

大意：差异叠加很大的缺陷在于它对噪声估计的时候是单道进行的，即与其它道的噪声水平不相关，这在实际中是不成立的，导致叠加效果有时候会很差。