各向异性介质中频率相关横波分裂参数的提取算法(英文)
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摘要
基于曾新吾和MacBeth提出的时域内双源累积旋转方法,建立了频率相关介质中分析多分量VSP数据的横波分裂参数提取算法(DCTF)。该算法可以在频域中针对单个频率提取横波各向异性参数(快横波的极化方向以及快、慢横波间的时间差),从而避免了目前常用方法中使用窄带通滤波可能带来的误差。通过对地震合成记录的数值分析,确定了该算法的可行性和正确性,并与目前常用方法的应用结果进行了比较。结果显示,频率相关横波分裂参数可以利用DCTF从地震四分量数据中直接提取。在地震频率范围内,含较大尺度裂缝时各向异性参数将表现出频率相关性,这意味着在地震频率范围会出现频散。随着频率的增加,各向异性有降低的趋势。
Based on the dual source cumulative rotation technique in the time-domain proposed by Zeng and MacBeth(1993),a new algebraic processing technique for extracting shear-wave splitting parameters from multi-component VSP data in frequency-dependent medium has been developed.By using this dual source cumulative rotation technique in the frequency-domain(DCTF),anisotropic parameters,including polarization direction of the shear-waves and timedelay between the fast and slow shear-waves,can be estimated for each frequency component in the frequency domain.It avoids the possible error which comes from using a narrow-band filter in the current commonly used method.By using synthetic seismograms,the feasibility and validity of the technique was tested and a comparison with the currently used method was also given.The results demonstrate that the shear-wave splitting parameters frequency dependence can be extracted directly from four-component seismic data using the DCTF.In the presence of larger scale fractures,substantial frequency dependence would be found in the seismic frequency range,which implies that dispersion would occur at seismic frequencies.Our study shows that shear-wave anisotropy decreases as frequency increases.
Based on the dual source cumulative rotation technique in the time-domain proposed by Zeng and MacBeth(1993),a new algebraic processing technique for extracting shear-wave splitting parameters from multi-component VSP data in frequency-dependent medium has been developed.By using this dual source cumulative rotation technique in the frequency-domain(DCTF),anisotropic parameters,including polarization direction of the shear-waves and timedelay between the fast and slow shear-waves,can be estimated for each frequency component in the frequency domain.It avoids the possible error which comes from using a narrow-band filter in the current commonly used method.By using synthetic seismograms,the feasibility and validity of the technique was tested and a comparison with the currently used method was also given.The results demonstrate that the shear-wave splitting parameters frequency dependence can be extracted directly from four-component seismic data using the DCTF.In the presence of larger scale fractures,substantial frequency dependence would be found in the seismic frequency range,which implies that dispersion would occur at seismic frequencies.Our study shows that shear-wave anisotropy decreases as frequency increases.
引文
Alford,R. M.,1986,Shear data in the presence of azimuthal anisotropy: 56th Ann. Internat. Mtg.,Soc. Expl. Geophys.,Expanded Abstracts,476 - 479.
Chapman,M.,2003,Frequency-dependent anisotropy due to meso-scale fractures in the presence of equant porosity: Geophysical Prospecting,51,369 - 379.
Crampin,S.,1985,Evaluation of anisotropy by shear-wave splitting: Geophysics,50,142 - 152.
Fryer,G. J.,and Frazer,L. N.,1984,Seismic waves in stratifi ed anisotropic media: Geophysical Journal of the Royal Astronomical Society,78,691 - 710.
Li,X. Y.,1997,Fractured reservoir delineation using multicomponent seismic data: Geophysical Prospecting,45,39 - 64.
Liu,E.,Crampin,S.,Queen,J. H.,and Rizer W. D.,1993,Velocity and attenuation anisotropy caused by microcracks and macrofractures in a multiazimuthal reverse VSP:Canadian Journal of Exploration Geophysics,27,177 - 188.
Maultzsch,S.,Chapman,M.,Liu,E. R.,and Li X.Y.,2003,Modeling frequency-dependent seismic anisotropy in uid-saturated rock with aligned fractures: implication of fracture size estimation from anisotropic measurements: Geophysical Prospecting,51,381 - 392.
Queen,J. H.,and Rizer,W. D.,1990,An integrated study of seismic anisotropy and the natural fracture system at the Conoco borehole test facility,Kay County,Oklahoma: Journal of Geophysical Research,95,255 - 274.
Tatham,R. B.,and McCormack,M. D.,1991,Multicomponent seismology in petroleum exploration: in Neitzel,E.B.,and Winterstein,D. F.,Eds.,Investigations in Geophysics,No. 6,Soc. Explor. Geophys.
Thomsen,L.,1995,Elastic anisotropy due to aligned cracks in porous rock: Geophysical Prospecting,43,805 - 829.
Winterstein,D. F.,and Meadows,M. A.,1991,Shear-wave polarizations and subsurface stress directions at Lost Hills fi eld: Geophysics,56(9),1331 - 1348.
Wu,J.,Gao,Y.,Shi,Y. T.,Zhao,X.,and Li J.-L.,2010,Tectonic stress analysis based on the crustal seismic anisotropy in Jiangsu and its adjacent area: Chinese Journal of Geophysics (in Chinese),53(7),1622 - 1630.
Zeng,X.,and MacBeth,C.,1993,Algebraic processing techniques for estimating shear-wave splitting in zerooffset VSP data: theory: Geophysical Prospecting,41(8),1033 - 1066.
Zeng,X.,MacBeth,C.,and Li,X. Y.,1997,Shear-wave VSP data processing for anisotropy: NUDT Press,Changsha (China).
Zhang,Z. J.,Teng,J.,Badal,J.,and Liu,E.,2009,Construction of regional and local seismic anisotropic structures from wide-angle seismic data: Crustal deformation in the southeast of China: Journal of Seismology,13(2),241 - 252.
Chapman,M.,2003,Frequency-dependent anisotropy due to meso-scale fractures in the presence of equant porosity: Geophysical Prospecting,51,369 - 379.
Crampin,S.,1985,Evaluation of anisotropy by shear-wave splitting: Geophysics,50,142 - 152.
Fryer,G. J.,and Frazer,L. N.,1984,Seismic waves in stratifi ed anisotropic media: Geophysical Journal of the Royal Astronomical Society,78,691 - 710.
Li,X. Y.,1997,Fractured reservoir delineation using multicomponent seismic data: Geophysical Prospecting,45,39 - 64.
Liu,E.,Crampin,S.,Queen,J. H.,and Rizer W. D.,1993,Velocity and attenuation anisotropy caused by microcracks and macrofractures in a multiazimuthal reverse VSP:Canadian Journal of Exploration Geophysics,27,177 - 188.
Maultzsch,S.,Chapman,M.,Liu,E. R.,and Li X.Y.,2003,Modeling frequency-dependent seismic anisotropy in uid-saturated rock with aligned fractures: implication of fracture size estimation from anisotropic measurements: Geophysical Prospecting,51,381 - 392.
Queen,J. H.,and Rizer,W. D.,1990,An integrated study of seismic anisotropy and the natural fracture system at the Conoco borehole test facility,Kay County,Oklahoma: Journal of Geophysical Research,95,255 - 274.
Tatham,R. B.,and McCormack,M. D.,1991,Multicomponent seismology in petroleum exploration: in Neitzel,E.B.,and Winterstein,D. F.,Eds.,Investigations in Geophysics,No. 6,Soc. Explor. Geophys.
Thomsen,L.,1995,Elastic anisotropy due to aligned cracks in porous rock: Geophysical Prospecting,43,805 - 829.
Winterstein,D. F.,and Meadows,M. A.,1991,Shear-wave polarizations and subsurface stress directions at Lost Hills fi eld: Geophysics,56(9),1331 - 1348.
Wu,J.,Gao,Y.,Shi,Y. T.,Zhao,X.,and Li J.-L.,2010,Tectonic stress analysis based on the crustal seismic anisotropy in Jiangsu and its adjacent area: Chinese Journal of Geophysics (in Chinese),53(7),1622 - 1630.
Zeng,X.,and MacBeth,C.,1993,Algebraic processing techniques for estimating shear-wave splitting in zerooffset VSP data: theory: Geophysical Prospecting,41(8),1033 - 1066.
Zeng,X.,MacBeth,C.,and Li,X. Y.,1997,Shear-wave VSP data processing for anisotropy: NUDT Press,Changsha (China).
Zhang,Z. J.,Teng,J.,Badal,J.,and Liu,E.,2009,Construction of regional and local seismic anisotropic structures from wide-angle seismic data: Crustal deformation in the southeast of China: Journal of Seismology,13(2),241 - 252.
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