基于局部相关加权的时域地震波束形成方法

定向地震波束能够加强主波束方向信号,但同时在主波束方向外产生畸变信号,导致多波束定向地震记录的信噪比降低。为此,依据地震波束定向记录中主波束方向内外的信号与原始信号之间的局部相关性差异提出了基于局部相关加权的时域地震波束形成方法。首先提取中心地震记录与延时后的地震记录或波束定向结果之间的局部最大相关系数谱,然后利用多种滤波方法和编码技术提高局部相关系数谱对有效信号的表征能力,最终实现对主波束信号的有效提取以及畸变信号的消除。理论模型数值实验结果表明,在波束定向前、后进行局部相关加权都能够准确提取主波束方向信号,消除畸变信号对有效信号的影响,改善地震记录和地震剖面的质量。

Seismic beam-forming is able to effectively strengthen the signals in look direction,but in the non-look direction,since there exist different delay times among different signals,the superposition signal will be distortion,it affects the recognition of the valid signal and reduces the signal-to-noise ratio of seismic records seriously.In order to solve the problem,this paper presents a method about the seismic beam-forming based on weighted local correlation to extract the signal in the look directional area and remove the interference of distorted signal.According to time-domain seismic beam-forming based on receiver array (TSBBRA) method,our method is developed based on the local correlation difference.Based on the reference of the original seismic record,two ways both extract the maximum local correlation spectrum between reference record and the delay record or the result with conventional beam-forming process firstly.Then time delay filter,single channel threshold filtering,multichannel median filtering,global threshold filtering and coding technique are used to filter the maximum local correlation.Finally the beam-forming signals in look direction are effectively extracted and the distortion signals are suppressed.The model test shows that the weighted local correlation beam-forming can protect the signal of look directional area,and suppress the distorted signal in the non-look directional area.Moreover,the new method improves quality of the common shot gather and stacked section and increases the signal-to-noise ratio of seismic data.

深部探测技术与实验研究专项SinoProbe-09-04(201011081)、SinoProbe-09-06(201311197和201011083)与高等学校博士学科点专项科研基金(20110061110053)联合资助。