一种相对保幅的低频逆时噪声压制方法及其应用

针对逆时偏移低频背景噪声压制问题,开展了相对保幅性去噪方法研究。从热力学传导方程出发,构建了三维扩散滤波数值计算公式并进行了简化,详细探讨了所提方法低频噪声的压制机理。以实际三维地震资料叠前逆时偏移数据为例,对比了邻点加权平滑滤波法、扩散滤波法和高通滤波法三种低频噪声压制方法的去噪效果及其频谱,同时对去噪前和去噪后的水平切片振幅曲线和深度域波形曲线进行相对保幅性分析。结果表明:扩散滤波方法可通过调节迭代次数实现不同压制程度的低频去噪效果,具有最佳的相对保幅性,同时频带更宽,频谱能量更均匀,这对实际资料逆时偏移处理具有重要的借鉴意义。

A relative amplitude preservation low-frequency reverse-time noise suppression method and its application

In order to suppress the low-frequency background noise of reverse-time migration, studies were carried out on noise suppression method of relatively amplitude preservation performance. Started from thermal conduction equation, 3D diffusion filter-ing numerical computational equation was constructed and simplified further for the detail discussion of the proposed method＆#39;s low-frequency noise suppression mechanism. Taking practical 3D seismic pre-stack reverse-time migration data as an example, noise suppression results and their spectrum of three kinds of low- frequency noise suppression methods, that is adjacent weighted smoothing filtering method, diffusion filtering method and high-pass filtering method were compared. Meanwhile, relatively ampli-tude preservation was analyzed on horizontal slice amplitude curve and waveform curve in depth domain before and after noise sup-pression. The results show that the diffusion filtering method can achieve low-frequency noise suppression in different suppression degree by adjusting the iterative frequency and has the best relatively amplitude preservation performance with wider frequency band and more even spectrum energy. Therefore, it has important model significance to the practical seismic reverse-time migra-tion data processing.