基于随机介质的提高地震记录分辨率的扩频方法

Spread spectrum method for improving seismic record resolution based on random medium

（中国地质大学地球物理系，湖北武汉430074）

Geophysics Department,China University of Geosciences,Wuhan 430074,China

常规提高地震记录分辨率的谱白化和反褶积等方法多以反射系数序列是白噪随机时间序列为前提，隐含着认为地下介质为白噪型随机介质这一问题。长期以来的勘探事实表明，地下介质不一定为白噪型随机介质，反射系数序列不一定是白噪随机时间序列。因此，常规方法有时不能得到符合实际的结果。除了白噪模型外，随机介质还有多种模型，不同类型的随机介质有着不同的性质，对应着不同的反射系数序列和地震记录。基于随机介质理论，研究了地震记录与随机介质统计参数之间的关系，提出了由实际地震记录求出随机介质统计参数、扩展地震记录频带的方法。理论模型和实际资料试处理结果表明，该方法可以得到与实际地质情况相符且分辨率大为提高的结果，是高分辨率地震资料处理中一个有意义的研究方向。

Conventional methods for improving seismic record resolution,such as spectrum whitening and deconvolution,assume that reflection coefficient sequence is white noise random time sequence,the prerequisite implicates that subsurface medium is white noise random medium.Prospecting experience indicates that not all subsurface medium is white noise random medium,not all reflection coefficient sequence is white noise random time sequence.Therefore,conventional methods can not obtain actual results sometimes.Except white noise model,random medium has many kinds of models;random medium in different type has different properties,which is corresponding to different reflection coefficient sequence and seismic record.Based on random medium theory,we studied the relationship between seismic record and random medium statistical parameters,and proposed the methods for obtaining random medium statistical parameters and spread seismic record frequency band from actual seismic record.Theoretical and actual data test result coincides with actual geological conditions,and the seismic data resolution has been greatly improved.The method is a meaningful research direction in high-resolution seismic data processing.