基于Cook距离的阻尼多道奇异谱分析分离绕射波

Damped multichannel singular spectrum analysis for diffraction separation based on the Cook⁃distance

地震绕射是提升小尺度不规则地质体成像横向分辨率的重要手段。常规地震记录中的绕射波会被能量强的反射波掩盖,因此需要分离出绕射波并成像。阻尼多道奇异谱分析是一种秩约束类的去噪方法,其原理为地震数据经过Hankel变换后做奇异值分解,反射波和绕射波分别对应着数值较大和较小的奇异值。然而该算法依赖人工确定反射波场的秩,不适用于海量地震数据处理。为了克服人工选择奇异值的问题,提出使用Cook距离作为自动计算反射波场秩的解决方案。将Cook距离和阻尼多道奇异谱分析算法相结合以实现反射和绕射波分离。模拟共炮检距道集和叠后实际数据实验表明,该方法能够有效获得高质量绕射波场。

Diffraction seismic exploration is a crucial technique for enhancing the lateral resolution of small‑scale geological structure imaging.Diffracted waves in conventional seismic records can be obscured by stronger energy reflected waves,making it necessary to separate these two wavefields for imaging purposes.Damped multi‑channel singular spectrum analysis(DMSSA)is a rank‑constrained denoising method that separates wavefields by decomposing the seismic data into a Hankel matrix and performing singular value decomposition.In this process,reflected and diffracted waves correspond to larger and smaller singular values respectively.However,this method relies on manually determining the rank of the reflected wavefield,which is impractical for processing large volumes of seismic data.To address the issue of manual selection,this paper proposes using Cook‑distance to automatically calculate the rank of the reflected wavefield.By combining Cook‑distance with the DMSSA algorithm,this paper achieved effective separation of reflected and diffracted waves.Experiments on common‑shot gathers and post‑stack data demonstrate that this method can successfully obtain high‑quality diffraction wavefields,highlighting the effectiveness of the proposed approach.