基于改进的广义S变换的地层吸收衰减补偿

Stratum absorption and attenuation compensation based on improved generalized S-transform

广义S变换采用时窗宽度随频率呈反比例变化的高斯窗函数,而改进的广义S变换采用宽度可变的高斯窗函数,其时窗宽度随频率呈正比例变化,即在低频段时窗较窄,获得较高的时间分辨率;高频段时窗较宽,获得很高的频率分辨率。此法更有利于进行地震波吸收衰减补偿。该方法能进行无损的广义S反变换,并能提取时变Q值,避免了传统方法中利用Q值补偿造成的欠补偿或过补偿问题。补偿后各时刻的时频谱变化趋势完全相同,地震记录的频带相同。此法用于实际VSP数据处理,结果表明利用该法进行吸收衰减补偿效果明显,有利于提高地震资料的分辨率,改善资料的品质。

The Gauss function whose window width changes in inverse proportion with frequency was used in generalized S-transform,while for improved generalized S-transform the variable width window was used,the window's width change with frequency was proportional.That is,the window is narrower for low frequency with the high time resolution,while the window is wider for high frequency with the high frequency resolution.With the new method the lossless generalized S-inverse transform can be conducted and time-dependent Q value can be estimated,so the under-compensation and over compensation which developed in traditional Q compensation method were avoided.After compensation,the variation trend of the time&frequency spectrum are exactly the same at every moment,and the seismic frequency bands are the same.Application of the new method in the field VSP data shows that the new method works very well for absorption and attenuation compensation,it also raises resolution and improves data quality.