径向道变换压制线性干扰改进方法及应用

Improvement of the Radial Trace Transformation to Attenuate Linear Noise and Application

径向道变换(RTT)是一个简单地震道的映射,即将地震道集振幅值从偏移距—双程旅行时(X-T)域变换到视速度—双程旅行时(R-T)域,在R-T域中线性干扰(如面波、直达波等)的频率会得到较大程度的降低从而可将其分离出来。在径向道变换过程中其基本运算为插值,为减小插值误差对线性干扰的影响,通过改进模拟-相减法,即在R-T域分离出噪音后再将原始资料和分离出的噪音反变换回X-T域,最后相减保幅即得去噪结果。通过理论模型和实际资料试验表明这种方法同传统模拟-相减法相比,能够降低插值误差对线性干扰的影响,使线性干扰得到有效压制,提高地震资料的信噪比。

The radial trace transformation （RTT） is the simple mapping operation that moves seismic wavefield amplitudes from the conventional coordinates of offset and travel- time（X--T） to those of apparent velocity and traveltime（R--T）. In the R--T domain, the frequency of the linear noise（surface wave ,direct wave ） can be decreased significantly, so the linear noise in the seismic data can be separated by the radial trace transformation. The basic arithmetic in the radial trace transformation is interpolation. By improving the model --subtract method to reduce the interpolation error of linear interference. After the wave- field separation in the R--T domain, the original data and the separated noise inverse trans- formation to the X--T domain, and finally the denoising result can be achieved through the subtraction and amplitude preservation. Model data and real data processing demonstrate that this method compared with the traditional model--subtract method, which can reduce the interpolation error of the linear noise and the linear noise can be suppressed and improve the S/N（signal to noise ratio） of seismic data.