基于最小平方滤波的面波压制方法

A method based on least-squares filter of seismic ground-roll suppression

在地震勘探中,强振幅、低频率的面波对于后续地震资料的处理和解释会产生重要影响。基于最小平方滤波的面波压制方法是一种新的面波压制方法,它与一般的频率域滤波方法不同。该方法的主要原理是利用扫描信号与滤波因子的褶积来预测面波,其中滤波因子的求取需要建立一个目标泛函。当目标泛函取得最小值时可从地震数据中求取滤波因子进而预测出面波,再将预测出的面波作为输入进行第二次面波预测,从地震记录中减去提取的面波,就得到去除面波后的地震数据。采用非线性的扫描信号提取面波,并对扫描信号起止频率进行了分析;通过对合成地震记录与煤田实际地震资料的处理,充分证明该方法能有效地压制面波。

In land seismic survey,the seismic data are mostly contaminated by ground-roll,which reduces the signal-to-noise ratio and impacts the quality of the seismic data seriously. The least-squares filter is a new means to suppress ground-roll,which is different from normal domain filter. The main principle of the method is the utilization of the convolution of scanning signal and filtering factor to predict ground-roll. It is necessary to construct the objective function to calculate the filter factor. The objective function is the leastsquares error of seismic data and ground-roll. In that way,the targeting functionally obtained minimum can calculate filter factors from seismic data. The last step is to continue the second ground-roll suppression by making the extracted ground-roll as the input,which can get the seismic data and wipe out the ground-roll. In this paper,nonlinear sweep signal was used to extract ground-roll,and the sweep signal＇s beginning-ending frequency was analyzed. The results prove that the proposed method can effectively suppress the surface wave through synthesis of field data.