稳定的迭代法反Q滤波

反Q滤波是补偿大地衰减效应的一种常用方法,但其振幅补偿的不稳定性限制了该方法在中、深层地震资料处理中的应用。为此本文提出了稳定的迭代反Q滤波法。首先对原始地震记录的频谱乘以一个对高频成分具有较强压制能力的低通滤波器,然后通过迭代法逐次逼近来弥补中、低频段振幅补偿不足的缺陷,由此得到了迭代法的递推公式。同时,本文还严格证明了迭代法的收敛性,并给出了迭代滤波的迭代通式。模型试验及振幅补偿算子滤波响应的对比分析结果表明:与常规反Q滤波方法相比,迭代滤波法不仅具有较强的抗噪声特性,而且对深层地震波具有较好的振幅补偿能力。在实际地震资料应用中,迭代滤波法对地震记录进行了稳定有效的能量补偿,显著地提高了中、深层地震资料的信噪比和分辨率。

A stable inverse Qfiltering using the iterative filtering method

The inverse Qfiltering is a useful method for the compensation of stratigraphic absorption. However,the instability of the amplitude compensation restricts the application of this method in seismic data processing for medium-and deep-seated strata.In the paper,we propose a stable inverse Qfiltering using the iterative filtering method.Firstly,the high frequency components can be suppressed effectively by a low-pass filter multiplying the spectrum of seismic records.Then we obtain the recursive formula of the iterative method. The successive approximation of iterative method can make up the instability of the amplitude compensation in the low and medium frequency components in inverse Qfiltering.The general formula of the iterative filtering method is obtained after the proved convergence.Model test and comparative analyses on the filter characteristics of the amplitude compensation operator indicate that the iterative filtering method shows a better performance in noise immunity and amplitude compensation in deep-seated strata seismic data in comparison than the common inverse Qfiltering methods.The proposed method is applied to the field seismic data. The attenuated seismic amplitude is compensated stably and effectively,and seismic data S/N ratio and resolution of the medium-and deep-seated strata are improved.