地震相干偏移与数据自参照偏移的关系
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摘要
地震相干偏移和数据自参照偏移是最近几年发展起来的地震成像新方法,并且已在地震勘探研究领域开始应用.该方法在VSP<垂直地震剖面)中的应用尤其值得关注,因为它部分地解决了一些在地面反射地震方法中难以解决的问题.地震相干偏移是用地震数据的互相关处理后的数据进行偏移,而数据自参照偏移则不必在偏移前对数据进行互相关处理,而是通过记录数据中的两个不同部分波场的延拓来互相参照进行偏移.二者的优点都是在偏移运算中可以不考虑原始震源位置、激发时间以及地震波初始传播路径.本文从偏移成像的理论出发分析了这两类算法,发现二者在成像原理上是一致的.本文还通过一个二维VSP多次波偏移的数值模拟实验,比较和归纳了这两类算法在实际应用中的特点.
Seismic interferometric migration and data-referenced-only migration are recently developed seismic migration methods that have found some new applications in seismic exploration. Especially in some VSP (Vertical Seismic Profiling) imaging applications, they have partially solved some problems that are very difficult to solve by using conventional surface seismic data. While the interferometric migration method migrates cross-correlated seismic data, the data-referenced-only migration method has no such apparent procedure. It extrapolates different parts of the recorded seismic wavefields and these extrapolated wavefields are referred to each other during imaging. Both methods have the merits that the original seismic source position, triggering time, and near-source properties can all be ignored for imaging. We analyze these two methods, and relate them to the same seismic migration theory. We also compare their results on a synthetic VSP multiples migration experiment, and discuss some of the practical issues of using these two methods.
Seismic interferometric migration and data-referenced-only migration are recently developed seismic migration methods that have found some new applications in seismic exploration. Especially in some VSP (Vertical Seismic Profiling) imaging applications, they have partially solved some problems that are very difficult to solve by using conventional surface seismic data. While the interferometric migration method migrates cross-correlated seismic data, the data-referenced-only migration method has no such apparent procedure. It extrapolates different parts of the recorded seismic wavefields and these extrapolated wavefields are referred to each other during imaging. Both methods have the merits that the original seismic source position, triggering time, and near-source properties can all be ignored for imaging. We analyze these two methods, and relate them to the same seismic migration theory. We also compare their results on a synthetic VSP multiples migration experiment, and discuss some of the practical issues of using these two methods.
引文
[1] Claerbout J F. Synthesis of a layered medium from its acoustic transmission response. Geophysics, 1968,33(2) :264-269
[2] Nowack R L S, Dasgupta G T, Schuster et al. Correlation migration using Gaussian beams of scattered teleseismic body waves. Bull. Seism. Soc. Am. ,2006,96:1-10
[3] Katz L. Inverse vertical seismic profiling while drilling: United States Patent, Patent Number: 5,012,453． 1991
[4] 常旭,李林新,刘伊克等.北京断陷黄庄-高丽营断层伪随机可控震源地震剖面.地球物理学报,2008,51(5) :1503-1510 Chang X, Li L X, Liu Y K, et al. Seismic profile of Huangzhuang-Gaoliying fault in Beijing by Mini-sosie method. Chinese J. Geophys. (in Chinese), 2008,51(5) :1503-1510
[5] Bakulin A, Calvert R. Virtual source: new method for imaging and 4D below complex overburden. 74th annual SEG meeting, Expanded Abstracts, 2004． 2477-2480
[6] Wapenaar K, Fokkema J. Green's function representation for seismic interferometry. Geophysics,2006 ,71(4) :S133-S146
[7] Yu J, Schuster G T. Enhancing illumination coverage of VSP data by crosscorrelation migration: 74~(th) annual SEG meeting,Expanded Abstract, 2004． 2501-2504
[8] Schuster G T. Theory of Daylight/Interferometric Imaging: Tutorial:63rd annual EAGE meeting, Expanded Abstracts,2001． A-32
[9] He R.Wave-equation interferometric migration of VSP data [Ph.D. thesis]. Utah:Univeristy of Utah. 2006
[10] Hornby B, Yu J. Interferometric imaging of a salt flank using walkaway VSP data. The Leading Edge , 2007,26:760-763
[11] Brandsberg-Dahl S, Van Gestel J P, Etgen J T, et al. VSP salt flank imaging through wavefield continuation: 65th annual EAGE conference, Extended Abstracts, B14． 2003
[12] He R, Hornby B, Schuster G T. 3D wave-equation interferometric migration of VSP free-surface multiples. Geophysics, 2007,72(5) :S195-S203
[13] He R, Karrenbach M, Paulsson B. VSP data-referenced-only migration without overburden: 78~(th) annual SEG meeting. Expanded Abstract, 2008,3405-3409
[14] Claerbout J F. Imaging the Earth' s interior. Black-well Scientific Publications, Inc. 1985
[15] Mehta K, Bakulin A, Sheiman J, et al. Improving the virtual source method by wavefield separation. Geophysics, 2007,72(4) :V79-V86
[2] Nowack R L S, Dasgupta G T, Schuster et al. Correlation migration using Gaussian beams of scattered teleseismic body waves. Bull. Seism. Soc. Am. ,2006,96:1-10
[3] Katz L. Inverse vertical seismic profiling while drilling: United States Patent, Patent Number: 5,012,453． 1991
[4] 常旭,李林新,刘伊克等.北京断陷黄庄-高丽营断层伪随机可控震源地震剖面.地球物理学报,2008,51(5) :1503-1510 Chang X, Li L X, Liu Y K, et al. Seismic profile of Huangzhuang-Gaoliying fault in Beijing by Mini-sosie method. Chinese J. Geophys. (in Chinese), 2008,51(5) :1503-1510
[5] Bakulin A, Calvert R. Virtual source: new method for imaging and 4D below complex overburden. 74th annual SEG meeting, Expanded Abstracts, 2004． 2477-2480
[6] Wapenaar K, Fokkema J. Green's function representation for seismic interferometry. Geophysics,2006 ,71(4) :S133-S146
[7] Yu J, Schuster G T. Enhancing illumination coverage of VSP data by crosscorrelation migration: 74~(th) annual SEG meeting,Expanded Abstract, 2004． 2501-2504
[8] Schuster G T. Theory of Daylight/Interferometric Imaging: Tutorial:63rd annual EAGE meeting, Expanded Abstracts,2001． A-32
[9] He R.Wave-equation interferometric migration of VSP data [Ph.D. thesis]. Utah:Univeristy of Utah. 2006
[10] Hornby B, Yu J. Interferometric imaging of a salt flank using walkaway VSP data. The Leading Edge , 2007,26:760-763
[11] Brandsberg-Dahl S, Van Gestel J P, Etgen J T, et al. VSP salt flank imaging through wavefield continuation: 65th annual EAGE conference, Extended Abstracts, B14． 2003
[12] He R, Hornby B, Schuster G T. 3D wave-equation interferometric migration of VSP free-surface multiples. Geophysics, 2007,72(5) :S195-S203
[13] He R, Karrenbach M, Paulsson B. VSP data-referenced-only migration without overburden: 78~(th) annual SEG meeting. Expanded Abstract, 2008,3405-3409
[14] Claerbout J F. Imaging the Earth' s interior. Black-well Scientific Publications, Inc. 1985
[15] Mehta K, Bakulin A, Sheiman J, et al. Improving the virtual source method by wavefield separation. Geophysics, 2007,72(4) :V79-V86
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