复杂地质体的地震波场成象方法研究
摘要
目前,常规的地震资料处理一般采用叠后偏移,它只能解决反射层归位和绕射波收敛,而不能解决倾斜界面的非共反射点叠加问题。而改进的方法是叠前部分偏移,它消除了地层倾角因素的影响,改善了CMP叠加效果。但DMO只是部分叠加,用DMO后的CMP道集做速度分析仍然受到速度分析点正下方周围倾斜反射层的影响,使速度分析结果受影响。因此,必须采用叠前深度偏移成像技术。
本文首先阐述了偏移的概念、偏移的基本原理等内容,对克希霍夫积分法和波动方程这两种叠前深度偏移的方法进行了详细的介绍,并简单的介绍了与克希霍夫积分法旅行时计算相关的射线追踪理论。最后通过Marmousi复杂断层模型、SEG盐丘模型和另外两个数据模型叠前深度偏移成象试验比较,得出克希霍夫积分法叠前深度偏移方法具有灵活的目标处理能力、可接受的成像效果、极高的计算效率。但该方法的缺陷是成像精度低、容易产生假频、振幅不保真、偏移孔径选择困难和多走时问题。而波动方程叠前深度偏移成像精度高、振幅保真、能体现地震波的动力学特征,但是波动方程的计算效率是目前急需解决的问题。另外通过数据处理,也得到了以下的几点认识和结论:
1、叠前时间偏移并不是一个独立的处理过程,其成像效果与基础处理密不可分。
2、速度场是直接影响偏移结果的关键,合理的、接近地质真实的、高精度的速度模型是叠前偏移获得高质量效果的前提。叠前偏移除了其算法本身外,剩下的工作主要就是建立速度模型。建立速度模型是一个复杂而费时的迭代过程。
3、对偏移孔径的实验可以在偏移质量和偏移效率中寻找到最佳的结合点。
At present, the routine seismic data processing is poststack migration, it just can not moves dipping reflector to their true subsurface positions and collapses diffractions. The improved way is prestack partial migration. It can avoid the influence of tilted stratum and yield an improved stacked section. But velocity analysis using CMP gathers after DMO is not exact. So, it must use prestack migration imaging technology.
Firstly, the paper shows the migration concepts, the basic theory of migration and so on, then I introduce two kinds of prestack migration methods which are kirchhoff integration migration and wave equation migration, also introduced to the ray tracing theory which related to calculate of travel time. Finally, The Marmousi complex fault model, the SEG salt dome model and the other two data model pre-stack depth migration imaging test show that Kirchhoff integration pre-stack depth migration method is flexible handling capacity of the target, acceptable The imaging results, high efficiency. The wave equation pre-stack depth migration can provide high precision, amplitude fidelity, but the time cost of calculation is expensive. In addition, through participating in this processing project, I summarize some recognitions and conclusions:
1.Prestack time migration is not an independent process,and its imaging result is tightly related with the basic process.
2.Velocity filed is a key aspect which directly affects migration result. Rational and high precise velocity model closed to the real geology is precondition to get high quality by prestack depth migration.
3.We can tack both the migration quality and migration efficiency into account and choose the best value of migration aperture in the experiment.
本文首先阐述了偏移的概念、偏移的基本原理等内容,对克希霍夫积分法和波动方程这两种叠前深度偏移的方法进行了详细的介绍,并简单的介绍了与克希霍夫积分法旅行时计算相关的射线追踪理论。最后通过Marmousi复杂断层模型、SEG盐丘模型和另外两个数据模型叠前深度偏移成象试验比较,得出克希霍夫积分法叠前深度偏移方法具有灵活的目标处理能力、可接受的成像效果、极高的计算效率。但该方法的缺陷是成像精度低、容易产生假频、振幅不保真、偏移孔径选择困难和多走时问题。而波动方程叠前深度偏移成像精度高、振幅保真、能体现地震波的动力学特征,但是波动方程的计算效率是目前急需解决的问题。另外通过数据处理,也得到了以下的几点认识和结论:
1、叠前时间偏移并不是一个独立的处理过程,其成像效果与基础处理密不可分。
2、速度场是直接影响偏移结果的关键,合理的、接近地质真实的、高精度的速度模型是叠前偏移获得高质量效果的前提。叠前偏移除了其算法本身外,剩下的工作主要就是建立速度模型。建立速度模型是一个复杂而费时的迭代过程。
3、对偏移孔径的实验可以在偏移质量和偏移效率中寻找到最佳的结合点。
At present, the routine seismic data processing is poststack migration, it just can not moves dipping reflector to their true subsurface positions and collapses diffractions. The improved way is prestack partial migration. It can avoid the influence of tilted stratum and yield an improved stacked section. But velocity analysis using CMP gathers after DMO is not exact. So, it must use prestack migration imaging technology.
Firstly, the paper shows the migration concepts, the basic theory of migration and so on, then I introduce two kinds of prestack migration methods which are kirchhoff integration migration and wave equation migration, also introduced to the ray tracing theory which related to calculate of travel time. Finally, The Marmousi complex fault model, the SEG salt dome model and the other two data model pre-stack depth migration imaging test show that Kirchhoff integration pre-stack depth migration method is flexible handling capacity of the target, acceptable The imaging results, high efficiency. The wave equation pre-stack depth migration can provide high precision, amplitude fidelity, but the time cost of calculation is expensive. In addition, through participating in this processing project, I summarize some recognitions and conclusions:
1.Prestack time migration is not an independent process,and its imaging result is tightly related with the basic process.
2.Velocity filed is a key aspect which directly affects migration result. Rational and high precise velocity model closed to the real geology is precondition to get high quality by prestack depth migration.
3.We can tack both the migration quality and migration efficiency into account and choose the best value of migration aperture in the experiment.
引文
[1]贺振华、黄德济、胡光岷等著.复杂油气藏地震波场特征方法理论及应用.成都:四川科学技术出版社,1999
[2]黄德济、贺振华、包吉山,地震勘探资料数据处理,北京:地质出版社,1990
[3]伊文,W.著,刘光鼎译,层状介质中的弹性波,科学出版社,1966
[4]三维叠前深度偏移实施及实例,国外油气勘探,Vol.6,1994,P96-99
[5]何樵登,应用地球物理教程-地震勘探,地质出版社,1980.
[6]黄绪德等译,[美]渥.伊尔马滋著,地震数据处理,石油工业出版社,1994.
[7]张钋、刘洪等,射线追踪方法的发展现状,地球物理学进展,2000年3月,第15卷,第一期.
[8]刘殿秘,网格法射线追踪研究及应用,吉林大学硕士学位论文,2004
[9]郭爱华,叠前时间偏移技术的应用研,中国地质大学(北京)硕士学位论文,2006
[10]马在田,地震成像技术,北京:石油工业出版社,1989
[11]牟永光,地震勘探资料数字处理方法,北京:石油工业出版社,1981
[12]陈志德,刘振宽,李成斌,高精度克希霍夫三维叠前深度偏移及并行实现,大庆石油地质与开发,2001,20(3),64-67
[13]王华忠,程玖兵,马在田,中点--偏移道集二维波动方程叠前深度偏移,见同济大学海洋地球物理系编,反射地震学论文集,上海:同济人学出版社,2000.102-108
[14]Paul Sava and Sergey Fomel,Huygens wavefront tracing:A robust alternative to ray tracing,Stanford University
[15]V.Cerveny.Seismic Ray Theory,Cambridge Univ.Press,Cambridge,1997.
[16]He Zhenhua,Xiong Gaojun and Zhang Yixiang,1998,Nonzero offset seismic forward modeling by one-way acoustic wave equation,68~(th)Annual Internat.Mtg.,Soc.Expl.Geophys.,Expanded Abstracts,1921-1924
[17]P.L.Stoffa,J.T.Fokkema,R.M.De Luna Freire and W.P.Kessinger,1990,Split-step Fourier migration,Geophysics vol.55,No.4,410-412
[18]Alexander Mihai Pouovici,1996,Prestack migration by split-step DSR,Geophysics vol.61,No.5,1412-1416
[19]Lian-Jie Huang,Michael Fehler,and Peter Roberts,1998,Extended local Rytov Fourier migration method,68~(th)Annual Internat.Mtg.,Soc.Expl.Geophys,Expanded Abstracts
[20]Ru-Shan Wu,Shengwen Jin,1998,Windowed GSP(Generalized Screen Propagators)Migration Applied to SEG-EAEG Salt Moldel Data,68~(th)Annual Internet.Mtg.,Soc.Expl.Geophys,Expanded Abstracts
[21]Lian-Jie Huang,Michael Fehler and Ru-Shan Wu,Extended local Born Fourier migration method,Geophysics,64(1),1999,1535-1545
[22]Gerard T.Schuster and Jianxing Hu,Green's function for migration:Continuous recording geometry,Geophysics,65(1),2000,167-175
[23]Guy Chavent and Rene-Edouard Plessix,An optimal true-amplitude least-squares prestack depth-migration operator,Geophysics,64(2),1999,508-515
[24]James A.Sethian and A.Mihai Popovic,3-D traveltime computation using the fast marching method,Geophysics,64(2),1999,516-523
[25]Lian-Jie Huang,Michael Fehler,and Peter Roberts,1999,Extended local Rytov Fourier migration method, Geophysics, 64(1), 1999,1524-1534
[26] Irene Kelly and Larry R.Lines, Optimization and sensitivity analysis of seismic depth migrations from Hibernia Field, Geophysics, 63(6), 1998,2054-2062
[27] Andrzej Kostecki and Anna Potchtopek, Stable depth extrapolation of seismic wavefields by a Neumann series, Geophysics, 63(6), 1998,2063-2071
[28] Hans J. Tieman, Migraiton velocity analysis: Accounting for the effects of lateral velocity variations: Geophysics, 60(1), 1995,164-175
[29] Ru-Shan Wu, 1994, Wide-angle elastic wave one-way propagation in heterogeneous media and an elastic wave complex-screen method, J.Geophys. Res, 99,751-761
[30] Gary F.Margrave and Robert J.Ferguson, Wavefield extrapolation by nonstationary phase shift, Geophysics, 64(4), 1999,1067-1078
[31] Gary F.Margrave, Theory of nonstationary linear filtering in the Fourier domain with application to time-variant filtering, Geophysics, 63(1), 1998,244-259
[32] B.O.Ekren and Bjorn Ursin, True-amplitude frequency-wavenumber constant-offset migration, Geophysics, 64(3), 1999,915-924
[33] Hale, D., Stable explicit depth extrapolation of seismic wave fields, Geophysics, 56(6), 1999,1770-1777
[34] Chengshu Wang, 1997, Some topics related to phase shift migration, 67~(th) Annual Internat. Mtg., Soc. Expl. Geophys, Expanded Abstracts
[35] Maria Teresa Arienti, Luca Cazzola, 1998,3-D post-stack depth migration: a comparison of wave equation techniques, 68~(th) Annual Internat. Mtg., Soc. Expl. Geophys, Expanded Abstracts
[36] Von Seggern, D., Spatial resolution of acoustic imaging with the Born approximation, Geophysics, Vol.56, No.3,1991,1185—1202
[37] Claerbout,J.,Image the earth's interior, Black Scientific Publication, 1985
[38] Dietrich Ristow, Fouier Finite-difference migration, Geophysics, Vol.59, No. 12, 1994, P. 1882-1993.
[39] Dietrich Ristow et al,3-D implicit finite-difference migration by multi way spliting, Geophysics, Vol.62, No.2,1997,P554—567
[40] Gazdag,J., Wave equation migration with the phase-shift method, Vol.43, No.5, 1978, P1342-1351.
[41] Gazdag,J. & Sguazzero,P., Migration of seismic data by phase-shift plus interpolation, Vol.49, No.1,1984, P124-131
[42] H.-L. Liu et al,Finite-difference modeling of sonic wavefields with a dipping interface, Geophysics, Vol.62, No.4,1997, P1270—1277
[43] P.L.Stoffa, J.T.Fokkema, Split Fourier migration, geophysics, Vol.55, No.4,1990, P410—421
[44] Stolt,R.H., Migration by fourier transform, Geophysics, Vol.43, No.1,1978, P23—48
[45] Wapenaar, C.P.A. and Berkhout, 1989, Elastic wave field extrapolation: Redatuming of single- and multi-component seismic data, Elsevier Science Publ.Co., Inc
[46] Yafei Wu and George A.McMechan, Wave extrapolation in the spatial wavelet domain with application to poststack reverse-time migration, Geophysics, 63(2), 1998, 589-600
[47] Cohen,J.K., Hangin,F. and Bleistein,N., Three dimension Born inversion with an arbitrary reference, Geophysics, 51(5), 1986,1552-1558
[2]黄德济、贺振华、包吉山,地震勘探资料数据处理,北京:地质出版社,1990
[3]伊文,W.著,刘光鼎译,层状介质中的弹性波,科学出版社,1966
[4]三维叠前深度偏移实施及实例,国外油气勘探,Vol.6,1994,P96-99
[5]何樵登,应用地球物理教程-地震勘探,地质出版社,1980.
[6]黄绪德等译,[美]渥.伊尔马滋著,地震数据处理,石油工业出版社,1994.
[7]张钋、刘洪等,射线追踪方法的发展现状,地球物理学进展,2000年3月,第15卷,第一期.
[8]刘殿秘,网格法射线追踪研究及应用,吉林大学硕士学位论文,2004
[9]郭爱华,叠前时间偏移技术的应用研,中国地质大学(北京)硕士学位论文,2006
[10]马在田,地震成像技术,北京:石油工业出版社,1989
[11]牟永光,地震勘探资料数字处理方法,北京:石油工业出版社,1981
[12]陈志德,刘振宽,李成斌,高精度克希霍夫三维叠前深度偏移及并行实现,大庆石油地质与开发,2001,20(3),64-67
[13]王华忠,程玖兵,马在田,中点--偏移道集二维波动方程叠前深度偏移,见同济大学海洋地球物理系编,反射地震学论文集,上海:同济人学出版社,2000.102-108
[14]Paul Sava and Sergey Fomel,Huygens wavefront tracing:A robust alternative to ray tracing,Stanford University
[15]V.Cerveny.Seismic Ray Theory,Cambridge Univ.Press,Cambridge,1997.
[16]He Zhenhua,Xiong Gaojun and Zhang Yixiang,1998,Nonzero offset seismic forward modeling by one-way acoustic wave equation,68~(th)Annual Internat.Mtg.,Soc.Expl.Geophys.,Expanded Abstracts,1921-1924
[17]P.L.Stoffa,J.T.Fokkema,R.M.De Luna Freire and W.P.Kessinger,1990,Split-step Fourier migration,Geophysics vol.55,No.4,410-412
[18]Alexander Mihai Pouovici,1996,Prestack migration by split-step DSR,Geophysics vol.61,No.5,1412-1416
[19]Lian-Jie Huang,Michael Fehler,and Peter Roberts,1998,Extended local Rytov Fourier migration method,68~(th)Annual Internat.Mtg.,Soc.Expl.Geophys,Expanded Abstracts
[20]Ru-Shan Wu,Shengwen Jin,1998,Windowed GSP(Generalized Screen Propagators)Migration Applied to SEG-EAEG Salt Moldel Data,68~(th)Annual Internet.Mtg.,Soc.Expl.Geophys,Expanded Abstracts
[21]Lian-Jie Huang,Michael Fehler and Ru-Shan Wu,Extended local Born Fourier migration method,Geophysics,64(1),1999,1535-1545
[22]Gerard T.Schuster and Jianxing Hu,Green's function for migration:Continuous recording geometry,Geophysics,65(1),2000,167-175
[23]Guy Chavent and Rene-Edouard Plessix,An optimal true-amplitude least-squares prestack depth-migration operator,Geophysics,64(2),1999,508-515
[24]James A.Sethian and A.Mihai Popovic,3-D traveltime computation using the fast marching method,Geophysics,64(2),1999,516-523
[25]Lian-Jie Huang,Michael Fehler,and Peter Roberts,1999,Extended local Rytov Fourier migration method, Geophysics, 64(1), 1999,1524-1534
[26] Irene Kelly and Larry R.Lines, Optimization and sensitivity analysis of seismic depth migrations from Hibernia Field, Geophysics, 63(6), 1998,2054-2062
[27] Andrzej Kostecki and Anna Potchtopek, Stable depth extrapolation of seismic wavefields by a Neumann series, Geophysics, 63(6), 1998,2063-2071
[28] Hans J. Tieman, Migraiton velocity analysis: Accounting for the effects of lateral velocity variations: Geophysics, 60(1), 1995,164-175
[29] Ru-Shan Wu, 1994, Wide-angle elastic wave one-way propagation in heterogeneous media and an elastic wave complex-screen method, J.Geophys. Res, 99,751-761
[30] Gary F.Margrave and Robert J.Ferguson, Wavefield extrapolation by nonstationary phase shift, Geophysics, 64(4), 1999,1067-1078
[31] Gary F.Margrave, Theory of nonstationary linear filtering in the Fourier domain with application to time-variant filtering, Geophysics, 63(1), 1998,244-259
[32] B.O.Ekren and Bjorn Ursin, True-amplitude frequency-wavenumber constant-offset migration, Geophysics, 64(3), 1999,915-924
[33] Hale, D., Stable explicit depth extrapolation of seismic wave fields, Geophysics, 56(6), 1999,1770-1777
[34] Chengshu Wang, 1997, Some topics related to phase shift migration, 67~(th) Annual Internat. Mtg., Soc. Expl. Geophys, Expanded Abstracts
[35] Maria Teresa Arienti, Luca Cazzola, 1998,3-D post-stack depth migration: a comparison of wave equation techniques, 68~(th) Annual Internat. Mtg., Soc. Expl. Geophys, Expanded Abstracts
[36] Von Seggern, D., Spatial resolution of acoustic imaging with the Born approximation, Geophysics, Vol.56, No.3,1991,1185—1202
[37] Claerbout,J.,Image the earth's interior, Black Scientific Publication, 1985
[38] Dietrich Ristow, Fouier Finite-difference migration, Geophysics, Vol.59, No. 12, 1994, P. 1882-1993.
[39] Dietrich Ristow et al,3-D implicit finite-difference migration by multi way spliting, Geophysics, Vol.62, No.2,1997,P554—567
[40] Gazdag,J., Wave equation migration with the phase-shift method, Vol.43, No.5, 1978, P1342-1351.
[41] Gazdag,J. & Sguazzero,P., Migration of seismic data by phase-shift plus interpolation, Vol.49, No.1,1984, P124-131
[42] H.-L. Liu et al,Finite-difference modeling of sonic wavefields with a dipping interface, Geophysics, Vol.62, No.4,1997, P1270—1277
[43] P.L.Stoffa, J.T.Fokkema, Split Fourier migration, geophysics, Vol.55, No.4,1990, P410—421
[44] Stolt,R.H., Migration by fourier transform, Geophysics, Vol.43, No.1,1978, P23—48
[45] Wapenaar, C.P.A. and Berkhout, 1989, Elastic wave field extrapolation: Redatuming of single- and multi-component seismic data, Elsevier Science Publ.Co., Inc
[46] Yafei Wu and George A.McMechan, Wave extrapolation in the spatial wavelet domain with application to poststack reverse-time migration, Geophysics, 63(2), 1998, 589-600
[47] Cohen,J.K., Hangin,F. and Bleistein,N., Three dimension Born inversion with an arbitrary reference, Geophysics, 51(5), 1986,1552-1558