一种简便的海洋P-SV转换波叠前偏移成像处理方法

A simple PSTM imaging method for P-SV wave

在莺歌海盆地,地震模糊区的成像一直是勘探工作中的一大难题,1998年在该地区采集了多波地震资料,通过对P-SV波的处理,在模糊带成像方面取得了较好的处理效果[1]。在对常规P-SV波处理中的偏移技术等存在的特殊问题进行分析的基础上,提出了一种P-SV波叠前偏移处理的方法,该方法将输入道分选成共转换散射点道集(CCSP),在CCSP道集中,双程旅行时和等效炮检距之间满足双曲线关系,故而使得常规处理P-P波的Kirchhof叠前偏移在此也可以运用,至于速度分析它也可以运用P-P波的速度分析方式来进行,因此采用该方法简化了转换波的处理,同时也提高了P-SV波的成像效果。

How to improve the obscure-zone images is a very difficult problem in seismic exploration in Yinggehai basin. In order to resolve this problem, multi-wave seismic data were acquired in 1998 in the area. Through P-SV wave processing, good imaging was achieved in obscure zone. On the basis of analysis on special problems, in migration of processing P-SV waves, a new prestack migration technique for P-SV waves was put forward. This technique sorted raw data into common converted scattering points to form CCSP gather. In the CCSP gather, two-way travel time and equivalent offset accord with hyperbola relationship, so Kirchhoff prestack time migration used to conventional P-P wave can be applied to it. Velocity analysis can also be processed by P-P wave method. Therefore this technique simplifies P-SV processing flow and improves P-SV image result.