VTI介质中的地层弹性参数反演
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摘要
在ＶＴＩ介质中,用非双曲线可以很好地近似Ｐ—Ｐ波中长排列情况下的旅行时;而对于Ｐ－ＳＶ波来说,应用非双曲线却不能很好地近似Ｐ－ＳＶ波的旅行时。对Ｐ－Ｐ波、Ｐ－ＳＶ波的旅行时进行三项泰勒展开时,它们的系数却包含了地震波的各向异性信息及其垂直速度信息,这为地震波的弹性参数反演提供了基础。实验分析表明,在中等排列长度下可以精确地得到Ｐ—Ｐ波、Ｐ—ＳＶ波旅行时的三项泰勒展式系数,从而可以精确地进行地层弹性参数反演。
In VTI media, P - P wave traveltime curve can be approximated by a nonhyperbola for a long or middle spread, as for P - SV wave, nonhyperbola is not accurate enough to fit traveltime curve. Three - term Taylor series for t2 - x2 curves of P - P and P - SV waves over layered vertically transverse isotropic media are related to dimensionless parameters and vertical velocities of P - and S - wave, which provide a basis for seismic elastic parameter inversion. Only in middle spread, three- term Taylor series for t2 - x2 curves of P - P and P - SV waves can precisely be obtained in modeling analysis, meanwhile seismic elastic parameter inversion can'be implemented precisely too.
In VTI media, P - P wave traveltime curve can be approximated by a nonhyperbola for a long or middle spread, as for P - SV wave, nonhyperbola is not accurate enough to fit traveltime curve. Three - term Taylor series for t2 - x2 curves of P - P and P - SV waves over layered vertically transverse isotropic media are related to dimensionless parameters and vertical velocities of P - and S - wave, which provide a basis for seismic elastic parameter inversion. Only in middle spread, three- term Taylor series for t2 - x2 curves of P - P and P - SV waves can precisely be obtained in modeling analysis, meanwhile seismic elastic parameter inversion can'be implemented precisely too.
引文
[1]THOMSEN L．Weak elastic anisotropy[J]．Geophysics,1986,51:671-688．
[2]TSVANKIN L,THOMSEN L．Nonhyperbolic reflection moveout in anisotropic media[J]．Geophysics,1994,59:1290—1304．
[3]HAKE H,TANER T．Three-term Taylor series for t~2-x~2 curves of P-wave and S－wave over layered
transversely isotropic ground[J]．Geophysical Prospecting,1984,32:828—850．
[4]TSVANKIN I．Normal moveout from dipping reflectors in anisotropic media[J]．Geophysics,1995,60:268—284.
[2]TSVANKIN L,THOMSEN L．Nonhyperbolic reflection moveout in anisotropic media[J]．Geophysics,1994,59:1290—1304．
[3]HAKE H,TANER T．Three-term Taylor series for t~2-x~2 curves of P-wave and S－wave over layered
transversely isotropic ground[J]．Geophysical Prospecting,1984,32:828—850．
[4]TSVANKIN I．Normal moveout from dipping reflectors in anisotropic media[J]．Geophysics,1995,60:268—284.
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