一种叠前地震记录的全波场正反演方法
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摘要
利用叠前地震数据的振幅及旅行时信息进行叠前地震记录的全波场反演,可以得到比常规叠后波阻抗反演更丰富的储层物性参数。同其它地球物理反问题类似,叠前地震全波场反演也需要某种正演算法来合成叠前记录。因为层状弹性半空间的地震波传播规律足以模拟通常的AVO分析,这样就可用慢度法作为叠前地震记录的正演模拟方法。慢度法能够提供地震波场的完全解,其结果包含了一次波、多次波和转换波。叠前反演问题由遗传算法实现,并根据叠前反演这一特定的多参数非线性问题,设计了遗传算法的所有算子,使其能够最大限度地搜索解空间并有效地搜索到最优解。叠前反演得到的纵波速度、横波速度和密度可用于指导岩性和流体的识别。
With prestack seismic amplitude and travel-time
information, full wave field inversion can extract
much more physical properties of reservoir than Con-
ventional post-stack impedance inversioir. Similar to
other geophysical inverse problems, prestack wave
field inversion also needs a forward modeling algo-
rithm to synthesize prestack seismogram. Since the
wave propagation in stratified elastic half space is e-
nough for AVO analysis, the slowness approach can
be used as forward modeling algorithm. It can pro-
vide a complete solution of seismic wave field, inclu-
ding primary reflections, multiples and conversion
waves. In order to effectively search the solution
space and find the optimum model, the GA (genetic
algorithm) operators are defined based on the specific
multi-parameter nonlinear optimization problem. The
P and S-wave velocities and densities, which are de-
rived from the waveform inversion, are used as a
guide to identify lithology and fluid content.
With prestack seismic amplitude and travel-time
information, full wave field inversion can extract
much more physical properties of reservoir than Con-
ventional post-stack impedance inversioir. Similar to
other geophysical inverse problems, prestack wave
field inversion also needs a forward modeling algo-
rithm to synthesize prestack seismogram. Since the
wave propagation in stratified elastic half space is e-
nough for AVO analysis, the slowness approach can
be used as forward modeling algorithm. It can pro-
vide a complete solution of seismic wave field, inclu-
ding primary reflections, multiples and conversion
waves. In order to effectively search the solution
space and find the optimum model, the GA (genetic
algorithm) operators are defined based on the specific
multi-parameter nonlinear optimization problem. The
P and S-wave velocities and densities, which are de-
rived from the waveform inversion, are used as a
guide to identify lithology and fluid content.
引文
1 李建荣,王磊,王赟.开发地震的几个问题初探[J].石油物探,2003,42(2) :279～284．
2 Stoffa P L and Sen M K. Nonlinear multiparameter optimization using genetic algorithms: Inversion of planewave seismograms [J]. Geophysics, 1991, 56 (11) : 1 794～1 810
3 张永刚.地震波场数值模拟方法[J].石油物探,2003,42(2) :143～148
4 Kennett B L N. Seismic wave propagation in stratified media[M]. New York: Cambridge University Press,1983． 25～254
5 Fryer G J. A slowness approach to the reflectivity method of seismogram synthsis[J]. Geophysical Journal of Royal Astronomical Society, 1980, 63(3) : 747～758
6 寻浩,董敏煜,牟永光.各向异性介质中反射率法波场模拟及体波辐射图案[J].石油地球物理勘探,1997,32(5) :605～614
7 刘勇,康立山,陈毓屏.非数值并行算法[M].北京:科学出版社,1995． 22～37
2 Stoffa P L and Sen M K. Nonlinear multiparameter optimization using genetic algorithms: Inversion of planewave seismograms [J]. Geophysics, 1991, 56 (11) : 1 794～1 810
3 张永刚.地震波场数值模拟方法[J].石油物探,2003,42(2) :143～148
4 Kennett B L N. Seismic wave propagation in stratified media[M]. New York: Cambridge University Press,1983． 25～254
5 Fryer G J. A slowness approach to the reflectivity method of seismogram synthsis[J]. Geophysical Journal of Royal Astronomical Society, 1980, 63(3) : 747～758
6 寻浩,董敏煜,牟永光.各向异性介质中反射率法波场模拟及体波辐射图案[J].石油地球物理勘探,1997,32(5) :605～614
7 刘勇,康立山,陈毓屏.非数值并行算法[M].北京:科学出版社,1995． 22～37
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