分离瑞雷面波的非线性滤波方法研究
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摘要
石油地震勘探记录中的瑞雷面波是一种干扰波 ,在反褶积和叠加前必需首先将面波从炮记录中分离出来 ,以提高叠加剖面的信噪比。地震数据处理中压制频散瑞雷波通常是利用其低频特征采用高通滤波 ,或利用其低视速度传播特征采用f-K滤波的方法来实现。文章给出了一种分离瑞雷面波的新方法 ,在假设地表为非弹性自由边界条件的基础上 ,给出了从总垂直位移记录中分离纵波分量和横波分量的非线性滤波器 ,利用此非线性滤波器从常规地震记录中分离出的波场即为频散瑞雷面波。该算法通过Fourier变换来实现 ,但是它有别于常规的f-K域视速度滤波方法。通过对数值模拟记录和野外实际观测记录的处理结果分析 ,这种分离瑞雷面波的非线性滤波方法可以在实际地震数据处理中应用。
In petroleum seismic exploration records,Rayleigh waves belong in disturbing waves which should be removed from the records before deconvolution and stacking so as to raise signal-to-noise ratio.In seismic data processing,the dispersive Rayleigh waves' being compressed may be realized by use of high-pass filtering method in consideration of their low frequency features or by applying f-k filtering method according to their low apparent velocity propagating characteristics.A new method of removing Rayleigh waves is introduced in the paper.On the basis of regarding the earth surface as a non-elastic free boundary,a nonlinear filter of separating the compressional wave component and shear wave component from the total vertical motion records is presented and the waves separated from conventional seismic records by the nonlinear filter are the dispersive Rayleigh waves.Such a filtering algorithm may be realized by Fourier transform,but it is different from the conventional apparent velocity f-k filting method.Through analyzing the results of processing the numerical modeling records and real records,it was proved that this nonlinear filting method of removing Rayleigh waves may be applied to processing the actual seismic data.
In petroleum seismic exploration records,Rayleigh waves belong in disturbing waves which should be removed from the records before deconvolution and stacking so as to raise signal-to-noise ratio.In seismic data processing,the dispersive Rayleigh waves' being compressed may be realized by use of high-pass filtering method in consideration of their low frequency features or by applying f-k filtering method according to their low apparent velocity propagating characteristics.A new method of removing Rayleigh waves is introduced in the paper.On the basis of regarding the earth surface as a non-elastic free boundary,a nonlinear filter of separating the compressional wave component and shear wave component from the total vertical motion records is presented and the waves separated from conventional seismic records by the nonlinear filter are the dispersive Rayleigh waves.Such a filtering algorithm may be realized by Fourier transform,but it is different from the conventional apparent velocity f-k filting method.Through analyzing the results of processing the numerical modeling records and real records,it was proved that this nonlinear filting method of removing Rayleigh waves may be applied to processing the actual seismic data.
引文
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2 YilmazO .Seismicdataprocessing.Oklahoma:SocietyofExplora tionGeophysicists,1987
3 尧德中.基于自由边界影响与偏振特性的纵横波分离方法.石油地球物理勘探,1998;33(2):198～203
4 耿建华,马在田,董良国.单分量地面记录波场分离非线性滤波方法.地球物理学报,2002;45:268～273
5 BenMenahemAetal.Seismicwavesandsources.SpringenVer lagNewYorkInc,1981
6 VidaleJE ,RobertW ,Clayton.Astablefree surfaceboundaryconditionfortwo dimensionalelasticfinite differencewavesimu lation.Geophysics,1986;51(12):2247—2249
7 CarcioneJM .Rayleighwavesinisotropicviscoelasticmedia.GeophysicalInt,1992;108:453—464
8 ManningPM ,MargraveGF .Rayleighwavemodelingbyfinitedifference.SEGExpandedAbstracts,1999
9 OhminatoT ,ChouetBA .AFree surfaceboundaryconditionforincluding3Dtopographyinthefinite differencemethod.BulletinoftheSeismologicalSocietyAmerica,1997;87(2):494—515
10 BielskiWR ,MatysiakSJ.Surfacewavesinperiodictwo layeredelastichalf space.ActaMechanica,1992;91:47—55
11 MunasingheM ,FarnellGW .Finitedifferenceanalysisofray leighwavescatteringatverticaldiscontinuities.GeophysicalRe search,1973;78(14):2454—2466
12 LevanderAR .Finitedifferencecalculationsofdispersiveray leighwavepropagation.Tectonophysics,1985;113:1—30
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