利用局部τ-p变换增强叠后地震信号

Enhancement of post-stack seismic signals using partial τ-p transform

τ-p变换在地震数字处理中有广泛的应用。τ-p域中的τ为直线方程t=τ+px在x=0时的时间轴上的截距,这种形式的τ-p变换称为全τ-p变换。若将时间轴平移至x=x_m时,则此种形式的π-p变换称为局部τ-p变换。局部τ-p变换并不改变全τ-p变换所具有的特点,但可以节省计算工作量。局部τ-p变换可以用于增强叠后地震信号,和通常的相干加强作用十分相似。局部τ-p变换和相干加强在计算中都要计算相似系数,所不同的是计算权系数的方法,前者使用相似系数加一个门槛值,后者采用对相似系数作平滑处理。实践表明,局部τ-p变换增强信号的效果要好于相干加强处理的效果。

τ-p transform is widely used in seismic data processing. In τ-p domain, τ is the intercept which is produced because line τ=px+τ cuts τ-axis (x=0). Such a τ-p transform is called full τ-p transform. If time τ-axis is translated to the position where x=x_m, the τ-p transform is called partial τ-p transform. Partial τ-p transform not only has the properties of full τ-p transform but also takes less calculation.Partial τ-p transform may enhance post-stack seismic signals,it quite functions as coherent enhancement. Both Partial τ-p transform and coherent enhancement need to calculate similarity coefficients, but they are different in methods for calculating weighting coefficients. The former calculates weighting coefficients by adding a threshold to the similar- ity coefficients,but the latter by smoothing the similarity coefficients. It has been practically shown that partial τ-p transform enhances seismic signals better than coherent enhancement does.