纵波VTI介质各向异性参数的求取
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摘要
在新疆塔里木盆地某地区的宽方位三维地震数据中,通过速度分析和不同炮检距范围数据的叠加剖面的比较,发现了各向同性基于双曲线时差曲线的NMO动校正时,远炮检距数据存在比较大的剩余动校正量。分析表明,是由于VTI介质火成岩的各向异性和垂向速度变化引起非双曲线时差。应用纵波短排列地震数据求取的均方根动校正速度,分别以扫描法和旅行时法得到了各自相互验证的各向异性参数。最后,利用所提取的各向异性参数,进行VTI介质各向异性速度分析、动校正和成像,剩余动校正得到消除,成像质量得到明显改善。
With the conventional P wave normal moveout correction based on hyperbolic moveout,the events on the far offset have a significant departure from hyperbolic moveout on CDP gather and long offset stacked section on wide azimuth seismic data in some areas of Tarim Basin.Nonhyperbolic moveout is caused by anisotropy and vertical inhomogeneity of velocity in VTI media.With the short offset RMS moveout velocity,the author obtained the anisotropic parameters by using scanning and traveltime inversion separately.The image was improved greatly by anisotropy velocity analysis in VTI media using the anisotropic parameters acquired.
With the conventional P wave normal moveout correction based on hyperbolic moveout,the events on the far offset have a significant departure from hyperbolic moveout on CDP gather and long offset stacked section on wide azimuth seismic data in some areas of Tarim Basin.Nonhyperbolic moveout is caused by anisotropy and vertical inhomogeneity of velocity in VTI media.With the short offset RMS moveout velocity,the author obtained the anisotropic parameters by using scanning and traveltime inversion separately.The image was improved greatly by anisotropy velocity analysis in VTI media using the anisotropic parameters acquired.
引文
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[2]Taner TM,Koehler F.Velocity spectra-D igital computer derivationand applications of velocity functions[J].Geoghysics,1969,24(4):859.
[3]Thom sen L A.W eak elastic an isotropy[J].Geophysics,1986,51.
[4]W right J.The effects of transverse isotropy on reflection amplitudeversus offset[J].Geophysics,1987,52:566.
[5]Lam er K.D ip-moveout error in transversely isotrop ic m ed ia w ithlinear velocity variation in depth[J].Geophysics,1993,58:1442.
[6]Lam er K,Cohen J.M igration error in transversely isotrop ic m ed iaw ith linear velocity variation in depth[J].Geophysics,1993,58:1454.
[7]Isaac JH,Lawton D C.Image m ispositioning due to dipping TImedia,a physical seism ic modeling study[J].Geophysics,1999,64:1230.
[8]Lawton D C,Isaac J H,Vestrum R W,et al.Slip-slid in'away-som epractical implications of seism ic velocity an isotropy on depth ima-ging[J].The Lead ing Edge,2001,20:70.
[9]A lkhalifah T,Tsvank in I.Velocity analysis in transversely isotrop icm ed ia[J].Geophysics,1995,60:1550.
[10]Grechka V,Tsvankin I.Feasibility of nonhyperbolic moveout inversionin transversely isotropic media[J].Geophysics,1998,63:957.
[11]G rechka V,Pech A,Tsvank in I,et al.Velocity analysis for tiltedtransversely isotrop ic m ed ia,A physical modelling example[J].Geophysics,2001,66:904.
[12]Le StunffY,G rechka V,Tsvank in I.D epth-domain velocity analysisin VTIm ed ia using surface P-wave data,Is it feasib le?[J].Ge-ophysics,2001,66:897.
[13]G rechka V,Theophan is S,Tsvank in I.Joint inversion of P-and PS-waves in orthorhomb ic m ed ia[J].Geophysics,1999,64:146.
[14]Tariq A lkhalifah.Velocity analysis using nonhyperbolic moveout intransversely isotrop ic m ed ia[J].Geophysics,1997,62:1839.
[2]Taner TM,Koehler F.Velocity spectra-D igital computer derivationand applications of velocity functions[J].Geoghysics,1969,24(4):859.
[3]Thom sen L A.W eak elastic an isotropy[J].Geophysics,1986,51.
[4]W right J.The effects of transverse isotropy on reflection amplitudeversus offset[J].Geophysics,1987,52:566.
[5]Lam er K.D ip-moveout error in transversely isotrop ic m ed ia w ithlinear velocity variation in depth[J].Geophysics,1993,58:1442.
[6]Lam er K,Cohen J.M igration error in transversely isotrop ic m ed iaw ith linear velocity variation in depth[J].Geophysics,1993,58:1454.
[7]Isaac JH,Lawton D C.Image m ispositioning due to dipping TImedia,a physical seism ic modeling study[J].Geophysics,1999,64:1230.
[8]Lawton D C,Isaac J H,Vestrum R W,et al.Slip-slid in'away-som epractical implications of seism ic velocity an isotropy on depth ima-ging[J].The Lead ing Edge,2001,20:70.
[9]A lkhalifah T,Tsvank in I.Velocity analysis in transversely isotrop icm ed ia[J].Geophysics,1995,60:1550.
[10]Grechka V,Tsvankin I.Feasibility of nonhyperbolic moveout inversionin transversely isotropic media[J].Geophysics,1998,63:957.
[11]G rechka V,Pech A,Tsvank in I,et al.Velocity analysis for tiltedtransversely isotrop ic m ed ia,A physical modelling example[J].Geophysics,2001,66:904.
[12]Le StunffY,G rechka V,Tsvank in I.D epth-domain velocity analysisin VTIm ed ia using surface P-wave data,Is it feasib le?[J].Ge-ophysics,2001,66:897.
[13]G rechka V,Theophan is S,Tsvank in I.Joint inversion of P-and PS-waves in orthorhomb ic m ed ia[J].Geophysics,1999,64:146.
[14]Tariq A lkhalifah.Velocity analysis using nonhyperbolic moveout intransversely isotrop ic m ed ia[J].Geophysics,1997,62:1839.
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