P-SV与P-P波的时间匹配
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摘要
本文针对叠前联合反演中的P-P波与P-SV波时间匹配问题进行了研究,认为将叠前时间偏移速度分析拾取的纵、横波速度比作为P-P波与P-SV波时间匹配的纵、横波速度比,匹配效果不是很好。文中利用数学模型正演模拟的数据,运用速度比扫描方法校正纵、横波匹配中的偏差,在扫描过程中根据构造成像的主要标志性层位确定大致时间及速度范围,选定计算时窗进行速度比扫描得到最佳速度比因子,从而完成匹配。将P-P波和P-SV波叠前时间匹配流程归纳为:①由P-P波和P-SV波速度分析得到速度比;②根据速度比模型进行叠前时间道集匹配;③如果匹配结果好则退出,反之则进行速度比扫描,更新速度比模型并转向②;④结束匹配,输出匹配道集或叠加剖面。数学模型数据和实际野外陆上地震资料的时间匹配效果表明,文中的P-P波与P-SV波时间匹配方法解决了纵、横波反演过程中来自同一地层界面反射同相轴的时间匹配问题,为后续的纵、横波联合反演提供了准确的道集数据。
In this paper the time matching between P-SV wave and P-P wave in pre-stack joint inversion was studied,it is believed that the matching effect is not great if the VP/VS ratio which is picked up from pre-stack time migration is used as VP/VS ratio in time matching between P-SV wave and P-P wave.By utilizing the datasets in mathematical model forward simulation in this paper,the VP/VS ratio scanning method could be used to correct the deviation in the matching between P-SV wave and P-P wave,based on the major makers in structural imaging the general time and velocity ranges in the scanning process can be determined,by selecting calculation window to conduct VP/VS ratio scanning the optimal VP/VS ratio factor was obtained,then the matching is completed.The workflow of the time matching between P-SV wave and P-P wave can be summarized as below:①To conduct P-P wave and P-SV wave velocity analysis and obtain VP/VS ratio;②Based on VP/VS ratio model the pre-stack the time gathers matching was conducted;③Evaluating the matching results,if satisfied then matching finishes,if not,continue the VP/VS ratio scanning,update the VP/VS ratio model and then go to step ② and ④.Finishing the matching,outputting the matching gathers or stacking sections.The matching effects between the mathematical model data and field land seismic data demonstrated that the method described in this paper solved the time matching problem for a reflection event from same subsurface interface in the P-P wave and P-SV wave inversion process,providing the accurate gather data for the subsequent joint inversion.
In this paper the time matching between P-SV wave and P-P wave in pre-stack joint inversion was studied,it is believed that the matching effect is not great if the VP/VS ratio which is picked up from pre-stack time migration is used as VP/VS ratio in time matching between P-SV wave and P-P wave.By utilizing the datasets in mathematical model forward simulation in this paper,the VP/VS ratio scanning method could be used to correct the deviation in the matching between P-SV wave and P-P wave,based on the major makers in structural imaging the general time and velocity ranges in the scanning process can be determined,by selecting calculation window to conduct VP/VS ratio scanning the optimal VP/VS ratio factor was obtained,then the matching is completed.The workflow of the time matching between P-SV wave and P-P wave can be summarized as below:①To conduct P-P wave and P-SV wave velocity analysis and obtain VP/VS ratio;②Based on VP/VS ratio model the pre-stack the time gathers matching was conducted;③Evaluating the matching results,if satisfied then matching finishes,if not,continue the VP/VS ratio scanning,update the VP/VS ratio model and then go to step ② and ④.Finishing the matching,outputting the matching gathers or stacking sections.The matching effects between the mathematical model data and field land seismic data demonstrated that the method described in this paper solved the time matching problem for a reflection event from same subsurface interface in the P-P wave and P-SV wave inversion process,providing the accurate gather data for the subsequent joint inversion.
引文
[1]Stewart R R,Gaiser J E,Brown R J and Lawton D C.Converted-wave seismic exploration:Methods.Geophysics,2002,67:1345～1363
[2]Tsvankin I and Thomsen L.Nonhyperbolic reflection moveout in anisotropic media.Geophysics,1994,59:1290～1304
[3]Tsvankin I and Grechka V.Dip moveout of converted waves and parameter esti mation in transversely iso-tropic media.Geophysical Prospecting,2000,48:257～292
[4]Li X Y.Converted-wave moveout analysis revisited:the search for a standard approach.SEG Technical Program Expanded Abstracts,2003,22:805～808
[5]Li X Y and Druzhinin A.A practical approach to P-SV prestack ti me migration and velocity analysis for transverse isotropy.SEG Technical Program Ex-panded Abstracts,2000,19:1142～1145
[6]Li X Y,Yuan J and Bale R.Converted-wave travel-ti me equations inlayered anisotropic media:An over-view.SEG Technical Program Expanded Abstracts,2003,22:105
[7]Cheret T,Bale R and Leaney S.Parameterization of polar anisotropic moveout for converted waves.SEG Technical Program Expanded Abstracts,2000,19:1181～1184
[8]Thomsen L.Converted-wave reflection seismology o-ver inhomogeneous,anisotropic media.Geophysics,1999,64:678～690
[9]Zhang Y.Non-hyperbolic converted wave velocity a-nalysis and normal moveout.SEG Technical Pro-gram Expanded Abstracts,1996,15:1555～1558
[10]Li X Y and Yuan J.Converted-wave moveout and conversion-point equationin layered VTI media:the-ory and application.Journal Applied Geophysics,2003,54:297～318
[11]Dai H.Integrative analysis of anisotropy parameter and velocities for PS converted waves.SEG Techni-cal Program Expanded Abstracts,2003,22:1577～1580
[12]Dai H,Li X Y and Conway P.3D pre-stack Kirch-hoff ti me migration of PS-waves and migration veloci-ty model building.SEG Technical Program Expand-ed Abstracts,2004,23:1115～1118
[2]Tsvankin I and Thomsen L.Nonhyperbolic reflection moveout in anisotropic media.Geophysics,1994,59:1290～1304
[3]Tsvankin I and Grechka V.Dip moveout of converted waves and parameter esti mation in transversely iso-tropic media.Geophysical Prospecting,2000,48:257～292
[4]Li X Y.Converted-wave moveout analysis revisited:the search for a standard approach.SEG Technical Program Expanded Abstracts,2003,22:805～808
[5]Li X Y and Druzhinin A.A practical approach to P-SV prestack ti me migration and velocity analysis for transverse isotropy.SEG Technical Program Ex-panded Abstracts,2000,19:1142～1145
[6]Li X Y,Yuan J and Bale R.Converted-wave travel-ti me equations inlayered anisotropic media:An over-view.SEG Technical Program Expanded Abstracts,2003,22:105
[7]Cheret T,Bale R and Leaney S.Parameterization of polar anisotropic moveout for converted waves.SEG Technical Program Expanded Abstracts,2000,19:1181～1184
[8]Thomsen L.Converted-wave reflection seismology o-ver inhomogeneous,anisotropic media.Geophysics,1999,64:678～690
[9]Zhang Y.Non-hyperbolic converted wave velocity a-nalysis and normal moveout.SEG Technical Pro-gram Expanded Abstracts,1996,15:1555～1558
[10]Li X Y and Yuan J.Converted-wave moveout and conversion-point equationin layered VTI media:the-ory and application.Journal Applied Geophysics,2003,54:297～318
[11]Dai H.Integrative analysis of anisotropy parameter and velocities for PS converted waves.SEG Techni-cal Program Expanded Abstracts,2003,22:1577～1580
[12]Dai H,Li X Y and Conway P.3D pre-stack Kirch-hoff ti me migration of PS-waves and migration veloci-ty model building.SEG Technical Program Expand-ed Abstracts,2004,23:1115～1118
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