小波变换在OBN地震资料双检合并中的研究与应用

Research and Application of Wavelet Transform in OBN Seismic Data Dual-sensor Summation

在OBN(Ocean Bottom Node)地震资料处理中,双检合并是目前认为最有效的检波点鬼波压制手段。利用水检与陆检对上行波和下行波的响应差异,通过标定求和,分离出上下行波场,达到压制检波点鬼波的目的。常规的双检合并方法都是基于单道或者单炮集进行振幅、相位等匹配,忽略了水检与陆检频率以及波场空间传播差异,难以求取精确的匹配算子,导致电缆鬼波压制效果差,严重制约了数据分辨率及真实地层的刻画。为提高双检合并效果,本文提出基于小波变换的双检合并技术。首先利用水检与陆检的仪器响应进行全局的相位及频率等方面的匹配,再将水检与陆检资料变换到小波域进行多尺度的局部自适应匹配后进行双检合并,最后再进行反变换,达到压制检波点鬼波的目的。通过理论模型测试结果表明,有力验证了所开发方法的准确性与有效性。通过实际数据应用结果表明,本方法相较于常规交叉鬼波化方法,检波点鬼波压制更干净,陷波频率补得更好,能够为后续处理提供更高品质的地震数据基础。

In OBN(ocean bottom node)seismic data processing,the dual-sensor summation is considered as the most effective method to suppress cable ghost wave.Based on the difference of P and Z components’sponses to upgoing and downgoing waves,the upgoing and downgoing wave fields are sep-arated by calibration and summation to achieve the purpose of suppressing cable ghost wave,which can not only improve the spectrum notch,widen the data frequency band,but also improve the data signal to noise ratio.Conventional double detection merging methods are based on single channel or single shot set for amplitude and phase matching,ignoring the differences in P and Z component frequencies and wave field spatial propagation,so it is difficult to obtain a more accurate matching operator.In this paper,a dual-sensor summation technique based on wavelet transform is proposed.Firstly,the global phase and frequency are matched by the responses of the water and land inspection instruments,then the water and land inspection data are transformed into the dual-tree complex wavelet domain.Before merging,multi-scale local adaptive matching and the inverse transformation are carried out to suppress the cable ghost wave.The application results of the model and the actual data show that the ghost wave suppression method is cleaner and the notch frequency is better,which provides high-quality seismic data for subsequent processing.