三维共散射点道集叠前时间偏移速度分析
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摘要
基于共散射点(CSP)道集的叠前时间偏移速度分析方法的理论基础是散射理论和Kirchhoff积分偏移方法。等价炮检距为研究叠前地震偏移和速度估计方法提供了新的思路。本文首先阐述了二维情况下单平方根旅行时方程的推导,以及共散射点道集的提取与构建,总结了共散射点道集的优势;在此基础上研究了三维情况下共散射点道集映射原理、构建方法及速度分析方法。实际三维资料的试算表明,共散射点道集对应的速度谱和叠前时间偏移剖面的精度高于常规CMP道集对应的速度谱和叠前时间偏移剖面。
Scattering theory and Kirchhoff pre-stack time migration methods are the theory basis of pre-stack time migration and velocity analysis methods on common scattering point(CSP) gathers.The concept of equivalent offset proposed in the paper provides a new approach for pre-stack migration and velocity analysis.This paper first derives a new kind of single-square-root travel-time equation,and a method to obtain CSP gathers,and summarize the advantage of CSP gathers compared to CMP gathers.And then the paper develops a CSP gathers method to 3D geometry data.Through the processing to 3D model and field data,it is clear that the quality of semblances and the imaging on CSP methods are better than those of CMP gathers.
Scattering theory and Kirchhoff pre-stack time migration methods are the theory basis of pre-stack time migration and velocity analysis methods on common scattering point(CSP) gathers.The concept of equivalent offset proposed in the paper provides a new approach for pre-stack migration and velocity analysis.This paper first derives a new kind of single-square-root travel-time equation,and a method to obtain CSP gathers,and summarize the advantage of CSP gathers compared to CMP gathers.And then the paper develops a CSP gathers method to 3D geometry data.Through the processing to 3D model and field data,it is clear that the quality of semblances and the imaging on CSP methods are better than those of CMP gathers.
引文
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[8]Bancroft J C,Geiger H D and Margrave G F.The e-quivalent offset method of prestack time migration.Geophysics,1998,63(6):2042～2053
[9]张凯.叠前偏移速度分析方法研究[博士学位论文].上海:同济大学,2008,22～30
[10]Schleicher J,Tygel M and Hubral P.3-D true-ampli-tude finite offset migration.Geophysics,1993,58(8):1112～1126
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[2]Deregowski S M.What is DMO.First Break,1986,5(7):7～24
[3]王华忠,徐蔚亚,徐兆涛等.DMO和叠前时间偏移的共同起点.石油地球物理勘探,2002,37(3):224～229Wang Huazhong,Xu Weiya,Xu Zhaotao et al.Thesame start of DMO and prestack time migration.OGP,2002,37(3):224～229
[4]Mayne W H.Common reflection point horizontal datastacking techniques.Geophysics,1962,27(7):927～938
[5]马在田等编著.计算地球物理学概论.上海:同济大学出版社,1997,65～80
[6]Fowler J F.A comparative overview of prestack timemigration methods.SEG Technical Program Ex-panded Abstracts,1997,16:1571～1574
[7]Zhang Kai,Cheng Jiubing and Ma Zaitian.Pre-stacktime migration and velocity analysis methods withcommon scatter-point gathers.Journal of Geophys-ics and Engineering,2006,3(3):283～289
[8]Bancroft J C,Geiger H D and Margrave G F.The e-quivalent offset method of prestack time migration.Geophysics,1998,63(6):2042～2053
[9]张凯.叠前偏移速度分析方法研究[博士学位论文].上海:同济大学,2008,22～30
[10]Schleicher J,Tygel M and Hubral P.3-D true-ampli-tude finite offset migration.Geophysics,1993,58(8):1112～1126
[11]Lumley D E,Clearbout J F,Bevc D.Anti-alisedKirchhoff 3-D migration.SEG Technical ProgramExpanded Abstracts,1999,18:1282～1285