【摘要】 与深层致密岩石相比,相对疏松的近地表地层严重吸收了地震波的高频成分,降低了地震数据的分辨率和高频成分的信噪比。本文利用井中雷管激发、地面检波器接收的微测井直达波资料,通过分析近地表地层不同传播距离的地震直达波频谱信息差异,采用维纳滤波方法,进行近地表吸收补偿反滤波器的求取,将不同微测井测量点对应的近地表吸收补偿反滤波器应用于相应的叠前共检波点道集地震数据,完成了叠前地震数据的空变吸收衰减补偿,克服了叠后地震数据无法实现空变补偿的难题。叠前三维地震近地表吸收补偿后的数据,较补偿前地震数据的优势信噪比频带宽度明显拓宽,低频成分基本保持,反射信息量有较大程度增加,而且与合成记录吻合更好,能更好的满足地质解释的需要,提高解释精度。更多还原

【Abstract】 High-frequency seismic data components can be seriously attenuated during seismic wave propagation in unconsolidated(low-velocity) layers,resulting in reduced seismic resolution and signal-to-noise(S/N) ratio.In this paper,first,based on Wiener filter theory,inverse filter calculations for near-surface absorption attenuation compensation were accomplished by analysis of the direct wave spectral components from different distances near the surface.The direct waves were generated by detonators in uphole shots and were acquired by receivers on the surface.The spatially varying inverse filters were designed to compensate for the frequency attenuation of 3D pre-stack CRG(common receiver-gather) data.After applying the filter to CRG data,the high frequency components were compensated with the low frequencies maintained.The seismic resolution and S/N ratio are enhanced and match better with synthetic seismograms and better meet the needs of geological interpretation.更多还原