伪深度域最小二乘逆时偏移方法及应用
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摘要
最小二乘逆时偏移基于反演的思想,能够消除偏移剖面中的假象,并得出振幅相对保真的反射率剖面,这对隐蔽储层识别、岩性油气藏勘探及四维地震具有重要的意义。但是,最小二乘逆时偏移需要利用多次迭代的策略,计算量及存储量巨大,在实际工业界的应用受到一定限制。本文尝试在伪深度域实现最小二乘逆时偏移,并采用了共轭梯度算法,在保证精度的情况下,大大节省了计算成本。伪深度域根据计算区域速度场分布转换到伪深度域后,网格采样点得到大大减少。在伪深度域进行计算,避免了高速区过采样,提高了计算效率。模型及实际资料处理结果表明该方法的正确性和有效性。该方法的实现可以提高最小二乘逆时偏移的实用性。
Least squares reverse-time migration(LSRTM) is an inversion method that removes artificial images and preserves the amplitude of reflectivity sections. LSRTM has been used in reservoir exploration and processing of 4D seismic data. LSRTM is, however, a computationally costly and memory-intensive method. In this study, LSRTM in the pseudodepth domain was combined with the conjugate gradient method to reduce the computational cost while maintaining precision. The velocity field in the depth domain was transformed to the velocity field in the pseudodepth domain; thus, the total number of vertical sampling points was reduced and oversampling was avoided. Synthetic and field data were used to validate the proposed method. LSRTM in the pseudodepth domain in conjunction with the conjugate gradient method shows potential in treating field data.
Least squares reverse-time migration(LSRTM) is an inversion method that removes artificial images and preserves the amplitude of reflectivity sections. LSRTM has been used in reservoir exploration and processing of 4D seismic data. LSRTM is, however, a computationally costly and memory-intensive method. In this study, LSRTM in the pseudodepth domain was combined with the conjugate gradient method to reduce the computational cost while maintaining precision. The velocity field in the depth domain was transformed to the velocity field in the pseudodepth domain; thus, the total number of vertical sampling points was reduced and oversampling was avoided. Synthetic and field data were used to validate the proposed method. LSRTM in the pseudodepth domain in conjunction with the conjugate gradient method shows potential in treating field data.
引文
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Chen,Y.Q.,Dutta G.,Dai,W.,and Schuster,G.T.,2017,Q-least-squares reverse time migration with viscoacoustic deblurring filters:Geophysics,82(6),425-438.
Dai,W.,and Schuster,J.,2009,Least-squares migration of simultaneous sources data with a deblurring filter:79th Annual Meeting,SEG,Extended Abstract,2990-2994.
Dai,W.,Boonyasiriwat,C.,and Schuster,G.T.,2010,3DMulti-source Least-squares Reverse Time Migration:80th Annual Meeting,SEG,Extended Abstract,3120-3124.
Dutta,G.,and Schuster,G.T.,2014,Attenuation compensation for least-squares reverse time migration using the viscoacoustic-wave equation:Geophysics,79(6),251-262.
Erlangga,Y.,Kees,V.,Kees,O.,Plessix,R.E.,and Mulder,W.A.,2004,A robust iterative solver for the two-way wave equation based on a complex shifted-Laplace preconditioner:74th Annual Meeting,SEG,Extended Abstract,1897-1900.
Li,G.H.,Feng,J.G.,and Zhu,G.M.,2011,Quasi-Pwave forward modeling in viscoelastic VTI media in frequency-space domain:Chinese Journal of Geophysic,54(1),200-207.
Li,Q.Y.,Huang,J.P.,and Li,Z.C.,2017,Crosscorrelation least-squares reverse time migration in the pseudo-time domain:Journal of Geophysics and Engineering,14(4),841-851.
Liu,H.W.,Ding,R.W.,Liu,L.,and Liu,H.,2013,Wavefield reconstruction methods for reverse time migration:Journal of Geophysics and Engineering,10(1),1-6.
Liu,L.,Ding,R.W.,Liu,H.W.,and Liu,H.,2015,3Dhybrid-domain full waveform inversion on GPU:Computers&Geosciences,83,27-36.
Ma,X.,and Alkhalifah,T.,2013,Wavefield extrapolation in pseudo-depth domain:Geophysics,78(2),81-91.
Schuster,G.T.,1993,Least-squares cross-well migration:63rd Annual Meeting,SEG,Extended Abstract,110-113.
Sun,J.Z.,Fomel,S.,Zhu,T.Y.,and Hu,J.W.,2016,Q-compensated least-squares reverse time migration using low-rank one-step wave extrapolation:Geophysics,81(4),271-279.
Sun,X.D.,Ge,Z.H.,and Li,Z.C.,2017,Conjugate gradient and cross-correlation based least-square reverse time migration and its application:Applied Geophysics,14(3),381-386.
Tang,Y.X.,2009,Target-oriented wave-equation leastsquares migration/inversion with phase-encoded Hessian:Geophysics,74(6),95-107.
Wong,M.,Ronen,S.,and Biondi,B.,2011,Least-squares reverse time migration/inversion for ocean bottom data:A case study:81st Annual Meeting,SEG,Extended Abstract,2369-2373.
Yang,S.T.,Wei,J.C.,Cheng,J.L.,Shi,L.Q.,and Wen,Z.J.,2016,Numerical simulations of full-wave fields and analysis of channel wave characteristics in 3-D coal mine roadway models:Applied Geophysics,13(4),621-630.
Zhang,D.L.,and Schuster,G.T.,2014,Least-squares reverse time migration of multiples:Geophysics,79(1),11-21.
Zhang,Y.,Duan,L.,and Xie,Y.,2013,A stable and practical implementation of least-squares reverse time migration:83rd Annual Meeting,SEG,Extended Abstract,3716-3720.
Chen,Y.Q.,Dutta G.,Dai,W.,and Schuster,G.T.,2017,Q-least-squares reverse time migration with viscoacoustic deblurring filters:Geophysics,82(6),425-438.
Dai,W.,and Schuster,J.,2009,Least-squares migration of simultaneous sources data with a deblurring filter:79th Annual Meeting,SEG,Extended Abstract,2990-2994.
Dai,W.,Boonyasiriwat,C.,and Schuster,G.T.,2010,3DMulti-source Least-squares Reverse Time Migration:80th Annual Meeting,SEG,Extended Abstract,3120-3124.
Dutta,G.,and Schuster,G.T.,2014,Attenuation compensation for least-squares reverse time migration using the viscoacoustic-wave equation:Geophysics,79(6),251-262.
Erlangga,Y.,Kees,V.,Kees,O.,Plessix,R.E.,and Mulder,W.A.,2004,A robust iterative solver for the two-way wave equation based on a complex shifted-Laplace preconditioner:74th Annual Meeting,SEG,Extended Abstract,1897-1900.
Li,G.H.,Feng,J.G.,and Zhu,G.M.,2011,Quasi-Pwave forward modeling in viscoelastic VTI media in frequency-space domain:Chinese Journal of Geophysic,54(1),200-207.
Li,Q.Y.,Huang,J.P.,and Li,Z.C.,2017,Crosscorrelation least-squares reverse time migration in the pseudo-time domain:Journal of Geophysics and Engineering,14(4),841-851.
Liu,H.W.,Ding,R.W.,Liu,L.,and Liu,H.,2013,Wavefield reconstruction methods for reverse time migration:Journal of Geophysics and Engineering,10(1),1-6.
Liu,L.,Ding,R.W.,Liu,H.W.,and Liu,H.,2015,3Dhybrid-domain full waveform inversion on GPU:Computers&Geosciences,83,27-36.
Ma,X.,and Alkhalifah,T.,2013,Wavefield extrapolation in pseudo-depth domain:Geophysics,78(2),81-91.
Schuster,G.T.,1993,Least-squares cross-well migration:63rd Annual Meeting,SEG,Extended Abstract,110-113.
Sun,J.Z.,Fomel,S.,Zhu,T.Y.,and Hu,J.W.,2016,Q-compensated least-squares reverse time migration using low-rank one-step wave extrapolation:Geophysics,81(4),271-279.
Sun,X.D.,Ge,Z.H.,and Li,Z.C.,2017,Conjugate gradient and cross-correlation based least-square reverse time migration and its application:Applied Geophysics,14(3),381-386.
Tang,Y.X.,2009,Target-oriented wave-equation leastsquares migration/inversion with phase-encoded Hessian:Geophysics,74(6),95-107.
Wong,M.,Ronen,S.,and Biondi,B.,2011,Least-squares reverse time migration/inversion for ocean bottom data:A case study:81st Annual Meeting,SEG,Extended Abstract,2369-2373.
Yang,S.T.,Wei,J.C.,Cheng,J.L.,Shi,L.Q.,and Wen,Z.J.,2016,Numerical simulations of full-wave fields and analysis of channel wave characteristics in 3-D coal mine roadway models:Applied Geophysics,13(4),621-630.
Zhang,D.L.,and Schuster,G.T.,2014,Least-squares reverse time migration of multiples:Geophysics,79(1),11-21.
Zhang,Y.,Duan,L.,and Xie,Y.,2013,A stable and practical implementation of least-squares reverse time migration:83rd Annual Meeting,SEG,Extended Abstract,3716-3720.