基于X形扩散滤波的逆时偏移低频噪声压制方法

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中图分类号：P631 文献标识码：A DOI：10.13810/j.cnki. issn.1000-7210.20240281

Abstract： Thereverse time migration（RTM） imaging method is highly favored for itsability to conduct imaging on complex geological structures without being constrained by the imaging angle. However，this method has its inherent low-frequency noise，thus significantly degradingthe migration imagingquality. Therefore，accurately suppressing the low-frequency noise of RTM is crucial for high-quality migration imaging results. Based on the conventional RTM approaches，this study conducts a detailed analysis of the mechanisms that generate low-frequency noise in RTM. Specifically，the Laplacian filtering method iscurrntly the most commonly adopted suppression method，but it still retains a portion of the low-frequency noise and alters the amplitude information of the seismic data.To this end，alow-frequency noise suppression method based on X-shaped diffusion filtering is proposed.This method is aglobal nonlinear iterative filtering approach that introduces a diffusion function derived from thermodynamics into the RTM noise suppression process，with the RTM data containing low-frequency noise taken as the input.Then，byadjusting the diffusion coeficient and the number of iterations，an X-shaped complementary denoising operator for complex dipping structures is introduced，and a damping function for difusion is set to flexibly control the difusion extent. This allows for the separation of effective signals and low-frequency noise in relatively amplitude-preserving conditions.Numerical simulations on both simple and complex models demonstrate that the X-shaped diffusion filtering method can quickly and ac curately suppress low-frequency noise in RTM and produce high-quality migration results. Keywords： reverse time migration，low-frequency noise，noise suppression，X-shaped diffusion filtering 姜大建，李振春，徐凯，等．基于X形扩散滤波的逆时偏移低频噪声压制方法[J].石油地球物理勘探，2025， 60（4） ：912-922. JIANG Dajian，LI Zhenchun，XU Kai，et al. Low-frequency noise suppression for reverse time migration based on X-shaped diffusion filtering[J]. Oil Geophysical Prospecting，2025，60（4） ：912-922.

0 引言

在地震勘探中，叠前偏移成像方法起着至关重要的作用。（剩余13825字）