基于改进二维聚合经验模态分解与频率域动态压制的煤层强反射主轴柔性抑制方法OA

In coal-bearing strata of transitional facies,the strong impedance contrast between the top and bottom interfaces of coal seams can generate high-energy strong reflection events,which significantly shield the weak internal reflections and pre-stack amplitude information,thereby restricting the fine characterization of coal-rock gas reservoirs and the accurate prediction of gas content.To address this engineering challenge,this paper proposes a flexible suppression method integrating improved Bi-dimensional Ensemble Empirical Mode Decomposition(BEEMD)and Frequency Domain Dynamic Attenuation(FDDA)for coal seam strong reflections with pre-stack seismic gathers as the object.The following results are obtained.First,with the application of BEEMD,multi-scale modal decomposition is achieved,a multi-attribute constrained discrimination mechanism based on correlation,dominant frequency shift,energy proportion within the strong-reflection time window,and spectral focusing rate is constructed,and a normalized comprehensive scoring function is established to realize adaptive identification of the dominant modal of strong reflections.Second,the FDDA based on bandwidth-adjustable Gaussian window function can effectively suppress the strong reflection axis while maximally preserving the weak internal reflections of the coal seam and their spectral structure.Third,the field application of the proposed method in the Mizhi area of the Ordos Basin demonstrates that it can significantly reduce the shielding effect of strong reflections,and improve the identifiability of weak reflections and pre-stack AVO characteristics.In conclusion,the BEEMD-FDDA integrated method can effectively improve the quality of seismic responses under strong reflection-dominated backgrounds,so as to provide reliable data support for coal seam internal structure identification,AVO analysis,and gas content prediction,and offer a feasible technical pathway for weak signal enhancement under complex reflection conditions.