Q叠前深度偏移在四川盆地薄层成像中的应用
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摘要
四川盆地表层结构复杂,目的层埋藏深(大于7000m),深层反射地震信号吸收衰减严重,地震信号能量弱、频率低、子波畸变严重,进而导致深层成像分辨率低,薄层识别困难。为了减小地层吸收对叠前深度偏移成像的影响,采用GeoEast软件系统开展了Q叠前Kirchhoff深度偏移应用研究。Q叠前Kirchhoff深度偏移通过引入复速度和复旅行时,严格按照波场传播路径对地层吸收造成的振幅衰减和频散效应进行振幅补偿与相位校正,以有效提高深层成像的保真度和分辨率。实际应用结果表明,相比常规叠前Kirchhoff深度偏移,Q叠前Kirchhoff深度偏移能显著改善偏移结果的振幅关系、拓宽有效频带、提高偏移成像的分辨率,使深层薄层容易识别追踪。
In Sichuan Basin,the near-surface is very complex.Targets are deeply buried(more than 7000 m).Weak reflections,low frequency,and distorted wavelet lead low resolution of deep imaging,and the thin bed identification becomes very difficult.In order to reduce the influence of absorption on prestack depth migration,the Q prestack Kirchhoff depth migration provided by GeoEast System is used.By introducing complex velocity and complex travel time,this prestack depth migration performs amplitude compensation and phase correction strictly according to the amplitude attenuation and dispersion effect caused by the formation absorption of the wave field,which can effectively improve the fidelity and resolution of deep imaging.Based on our application,the Qprestack Kirchhoff depth migration can significantly improve the am-plitude relationship,widen the frequency band,and enhance the migration imaging resolution compared with conventional prestack Kirchhoff depth migration,which makes thin beds much easier to be identified and tracked.
In Sichuan Basin,the near-surface is very complex.Targets are deeply buried(more than 7000 m).Weak reflections,low frequency,and distorted wavelet lead low resolution of deep imaging,and the thin bed identification becomes very difficult.In order to reduce the influence of absorption on prestack depth migration,the Q prestack Kirchhoff depth migration provided by GeoEast System is used.By introducing complex velocity and complex travel time,this prestack depth migration performs amplitude compensation and phase correction strictly according to the amplitude attenuation and dispersion effect caused by the formation absorption of the wave field,which can effectively improve the fidelity and resolution of deep imaging.Based on our application,the Qprestack Kirchhoff depth migration can significantly improve the am-plitude relationship,widen the frequency band,and enhance the migration imaging resolution compared with conventional prestack Kirchhoff depth migration,which makes thin beds much easier to be identified and tracked.
引文
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[12] 白敏.高斯束偏移方法与应用[D].北京:中国石油大学(北京),2016.BAI Min.Theory and Application of Gassian Beam Migration[D].China University of Petroleum(Beijing),Biejing,2016.
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[16] 张宇.从成像到反演:叠前深度偏移的理论、实践与发展[J].石油物探,2018,57(1):1-23.ZHANG Yu.From imaging to inversion:Theory,practice,and technological evolution of prestack depth migration[J].Geophysical Prospecting for Petroleum,2018,57(1):1-23.
[17] Traynin P,Liu J,Reilly J.Amplitude and bandwidth recovery beneath gas zones using Kirchhoff prestack depth Q-migration[C].SEG Technical Program Expanded Abstracts,2008,27:2412-2416.
[18] Cavalca M,Moore I,Zhang L,et al.Ray-based tomography for Q estimation and Q compensation in complex media[C].SEG Technical Program Expanded Abstracts,2011,30:3989-3993.
[2] 方伍宝,刘定进.深度域地震成像新技术理论与实践[M].北京:中国石化出版社,2014.
[3] 李振春.地震偏移成像技术研究现状与发展趋势[J].石油地球物理勘探,2014,49(1):1-21.LI Zhenchun.Research status and development trends for seismic migration technology[J].Oil Geophysical Prospecting,2014,49(1):1-21.
[4] 撒利明,杨午阳,杜启振,等.地震偏移成像技术回顾与展望[J].石油地球物理勘探,2015,50(5):1016-1036.SA Liming,YANG Wuyang,DU Qizhen,et al.Past,present,and future of seismic migration imaging[J].Oil Geophysical Prospecting,2015,50(5):1016-1036.
[5] Schneider W.Integral formulation for migration in two and three dimensions[J].Geophysics,1978,43(1):49-76.
[6] Biondi B.Kirchhoff imaging beyond aliasing[J].Geophysics,2001,66(2):654-666.
[7] Hill N.Gaussian beam migration[J].Geophysics,1990,55(11):1416-1428.
[8] Hill N.Prestack Gaussian-beam depth migration[J].Geophysics,2001,66(4):1240-1250.
[9] Gray S,Bleistein N.True-amplitude Gaussian-beam migration[J].Geophysics,2009,74(2):S11-S23.
[10] 岳玉波.复杂介质高斯束偏移成像方法研究[D].山东青岛:中国石油大学(华东),2011.YUE Yubo.Study on Gaussian Beam Migration Methods in Complex Medium[D].China University of Petroleum,Qingdao,2011.
[11] 高成.时间域高斯波束叠前深度偏移[D].吉林长春:吉林大学,2015.GAO Cheng.Gaussian Beam Prestack Depth Migration in Time Domain[D].Jilin University,Changchun,Jilin,2015.
[12] 白敏.高斯束偏移方法与应用[D].北京:中国石油大学(北京),2016.BAI Min.Theory and Application of Gassian Beam Migration[D].China University of Petroleum(Beijing),Biejing,2016.
[13] Baysal E,Kosloff D,Sherwood J.Reverse time migration[J].Geophysics,1983,48(11):1514-1524.
[14] Hildebrand S.Reverse-time depth migration:Impe-dance imaging condition[J].Geophysics,1987,52(8):1060-1064.
[15] Shragge J.Reverse time migration from topography[J].Geophysics,2014,79(4):S141-S152.
[16] 张宇.从成像到反演:叠前深度偏移的理论、实践与发展[J].石油物探,2018,57(1):1-23.ZHANG Yu.From imaging to inversion:Theory,practice,and technological evolution of prestack depth migration[J].Geophysical Prospecting for Petroleum,2018,57(1):1-23.
[17] Traynin P,Liu J,Reilly J.Amplitude and bandwidth recovery beneath gas zones using Kirchhoff prestack depth Q-migration[C].SEG Technical Program Expanded Abstracts,2008,27:2412-2416.
[18] Cavalca M,Moore I,Zhang L,et al.Ray-based tomography for Q estimation and Q compensation in complex media[C].SEG Technical Program Expanded Abstracts,2011,30:3989-3993.