VTI介质角度域叠前深度偏移
|
摘要
研究了VTI介质角度域偏移方法,以各向同性双平方根方程的角度域偏移方法为基础,从VTI介质qP波频散关系出发,推导出VTI介质角度域偏移的波场延拓算子;在频率—波数域处理以横向均匀速度传播的波场,在空间域处理具有速度扰动特征的波场以提高波场延拓精度。模型试算和实际资料处理结果表明:各向同性偏移方法由于未考虑各向异性参数的影响,绕射波不能完全收敛,波场聚焦效果差,降低了成像剖面的分辨率和信噪比,不能对地质构造精确成像;VTI介质角度域偏移可对断层、盐丘、小尺度地质体精确成像。对于角度域偏移产生的角度域共成像点道集(ADCIG)而言,各向同性偏移的ADCIG同相轴无法校平,残留断点绕射波,波场无法正确聚焦,不能正确反映局部地质特征;VTI介质偏移的ADCIG同相轴较平直,角度范围更宽,波场归位准确,精度较高。因此,利用VTI介质角度域偏移方法可对复杂构造精确成像。
The angle domain migration in VTI media is discussed in this paper.Based on the angle domain migration of isotropic double-square-root equation,a wavefield extension operator of angle domain migration in VTI media is derived from the qP wave dispersion equation.The complex velocity and anisotropic parameter field are divided into two parts,one is lateral uniform background field,and the other is the disturbances of velocity and anisotropic parameters.Then the wave propagated at a uniform velocity and anisotropy field is processed in the frequency wavenumber domain,and the wave propagated at a velocity and anisotropy disturbance field is corrected by time-shift in the spatial domain.So the accuracy of wave field extension is greatly improved.Based on our model and real data tests,the following observation are obtained:A.Because the isotropic migration method does not take into account the influence of anisotropy parameters,the diffraction wave cannot be completely converged and the wavefield is misfocused,which causes low resolution and low signal-to-noise ratio.So conventional migration methods cannot accurately image geological structures,while the VTI media migration can accurately image faults,salt mounds,and small scale geological bodies;B.For the angle domain common imaging gathers(ADCIGs)generated by the prestack migration,the event of the isotropic method cannot be equalized,the residual fault diffraction is wound and the wavefield cannot be properly focused,which cannot correctly reflect local geological characteristics,while the ADCIGs from VTI media migration are relatively straight,the angle range is wider,the wavefield is accurately positioned.So the image accuracy is higher.Therefore,the angle domain migration in VTI media can be suitable for complex-structure accurate imaging.
The angle domain migration in VTI media is discussed in this paper.Based on the angle domain migration of isotropic double-square-root equation,a wavefield extension operator of angle domain migration in VTI media is derived from the qP wave dispersion equation.The complex velocity and anisotropic parameter field are divided into two parts,one is lateral uniform background field,and the other is the disturbances of velocity and anisotropic parameters.Then the wave propagated at a uniform velocity and anisotropy field is processed in the frequency wavenumber domain,and the wave propagated at a velocity and anisotropy disturbance field is corrected by time-shift in the spatial domain.So the accuracy of wave field extension is greatly improved.Based on our model and real data tests,the following observation are obtained:A.Because the isotropic migration method does not take into account the influence of anisotropy parameters,the diffraction wave cannot be completely converged and the wavefield is misfocused,which causes low resolution and low signal-to-noise ratio.So conventional migration methods cannot accurately image geological structures,while the VTI media migration can accurately image faults,salt mounds,and small scale geological bodies;B.For the angle domain common imaging gathers(ADCIGs)generated by the prestack migration,the event of the isotropic method cannot be equalized,the residual fault diffraction is wound and the wavefield cannot be properly focused,which cannot correctly reflect local geological characteristics,while the ADCIGs from VTI media migration are relatively straight,the angle range is wider,the wavefield is accurately positioned.So the image accuracy is higher.Therefore,the angle domain migration in VTI media can be suitable for complex-structure accurate imaging.
引文
[1] Pommier A,Leinenweber K,Kohlstedt D L,et al.Experimental constraints on the electrical anisotropy of the lithosphere asthenosphere system[J].Nature,2015,522(3):202-206.
[2] 王赟,杨顶辉,殷长春,等.各向异性地球物理与矢量场[J].科学通报,2017,62(23):2595-2605.WANG Yun,YANG Dinghui,YIN Changchun,et al.Anisotropic geophysics and vector field[J].Chinese Science Bulletin,2017,62(23):2595-2605.
[3] 王咸彬.TTI各向异性逆时偏移技术[J].石油物探,2017,56(4):534-542.WANG Xianbin.Anisotropic reverse time migration technique in TTI media and its application[J].Geophysical Prospecting for Petroleun,2017,56(4):534-542.
[4] Alkhalifah T.An acoustic wave equation for aniso-tropic media[J].Geophysics,2000,65(4):1239-1250.
[5] 吴国忱,梁锴,王华忠.VTI介质qP波广义高阶屏单程传播算子[J].石油地球物理勘探,2007,42(6):640-650.WU Guochen,LIANG Kai,WANG Huazhong.High order one way generalized screen propagation operator of qP wave in VTI medium[J].Oil Geophysical Prospecting,2007,42(6):640-650.
[6] 韩建光,王赟,张晓波,等.VTI介质高斯束叠前深度偏移[J].石油地球物理勘探,2015,50(2):267-273.HAN Jianguang,WANG Yun,ZHANG Xiaobo,et al.Gaussian beam prestack depth migration in VTI media[J].Oil Geophysical Prospecting,2015,50(2):267-273.
[7] 韩建光,王赟,陈传绪,等.二维各向异性多波高斯束叠前深度偏移[J].地球物理学进展,2017,32(3):1130-1139.HAN Jianguang,WANG Yun,CHEN Chuanxu,et al.Multiwave Gaussian beam prestack depth migration for 2D anisotropic media[J].Progress in Geophysics,2017,32(3):1130-1139.
[8] 刘礼农,高红伟,刘洪,等.三维VTI介质中波动方程深度偏移的最优分裂Fourier方法[J].地球物理学报,2005,48(2):406-414.LIU Linong,GAO Hongwei,LIU Hong,et al.Wave equation depth migration with optimum split step Fourier method in 3D VTI media[J].Chinese Journal of Geophysics,2005,48(2):406-414.
[9] 刘礼农,张剑锋.三维各向异性介质中的波动方程叠前深度偏移方法[J].地球物理学报,2011,54(11):2906-2915.LIU Linong,ZHANG Jianfeng.Wave equation prestack depth migration method in 3D VTI media[J].Chinese Journal of Geophysics,2011,54(11):2906-2915.
[10] 程玖兵,康玮,王腾飞.各向异性介质qP波传播描述Ⅰ:伪纯模式波动方程[J].地球物理学报,2013,56(10):3474-3486.CHENG Jiubing,KANG Wei,WANG Tengfei.Description of qP wave propagation in anisotropic media,Part Ⅰ:Pseudo-pure-mode wave equation[J].Chinese Journal of Geophysics,2013,56(10):3474-3486.
[11] 程玖兵,陈茂根,王腾飞,等.各向异性介质qP波传播描述Ⅱ:分离纯模式标量波[J].地球物理学报,2014,57(10):3389-3401.CHENG Jiubing,CHEN Maogen,WANG Tenfei,et al.Description of qP wave propagation in anisotropic media,Part Ⅱ:Separation of pure-mode scalar wave[J].Chinese Journal of Geophysics ,2014,57(10):3389-3401.
[12] Sun X D,Ge Z H,Li Z C,et al.The stability problem of reverse time migration for viscoacoustic VTI media[J].Applied Geophysics,2016,13(4):608-613.
[13] Zhang J M,He B S,Tang H G.Pure quasi P wave equation and numerical solution in 3D TTI media [J].Applied Geophysics,2017,14(1):125-132.
[14] Hua B ,Lencrerot R ,Williamson P ,et al.High-order and high-accuracy 3D Fourier finite difference depth migration with an optimally reduced coefficient table for the tilted transversely isotropic media[C].SEG Technical Program Expanded Abstracts,2013,32:3794-3798.
[15] 黄建平,朱峰,李振春,等.VTI介质FFD叠前深度偏移成像方法[J].石油地球物理勘探,2017,52(3):491-501.HUANG Jianping,ZHU Feng,LI Zhenchun,et al.FFD prestack depth migration imaging method for VTI medium[J].Oil Geophysical Prospecting,2017,52(3):491-501.
[16] 朱峰,黄建平,李振春.黏声VTI介质傅里叶有限差分叠前深度偏移[J].石油地球物理勘探,2017,52(5):956-966.ZHU Feng,HUANG Jianping,LI Zhenchun.FFD prestack depth migration for visco-acoustic VTI me-dium[J].Oil Geophysical Prospecting,2017,52(5):956-966.
[17] Hoop D E,Le Rousseau J H,Wu R S.Generalization of the phase approximation for the scattering of acoustic waves[J].Wave Motion,2000,31(1):43-70.
[18] Xu S,Chauris H,Lambare G,et al.Common angle migration:A strategy for imaging complex media[J].Geophysics,2001,66(6):1877-1894.
[19] Stork C,Symes W.Kinematic artifacts in prestack depth migration[J].Geophysics,2004,69(2):562-575.
[20] Xie X,Wu R.Extracting angle domain information from migration wave field[C].SEG Technical Program Expanded Abstracts,2002,21:1360-1363.
[21] James E,Rickett J E,Save P C.Offset and angle domain common image point gather for shot profile migration[J].Geophysics,2002,67(3):883-889.
[22] Save P,Fomel S.Angle domain common image gathers by wave field continuation[J].Geophysics,2003,68(3):1065-1074.
[23] Biondi B.Angle domain common image gathers from anisotropic migration[J].Geophysics,2007,72(2):S81-91.
[24] 李振春,朱莉,叶月明,等.角度域共成像点道集的提取与叠加成像[J].石油物探,2008,47(6):567-572.LI Zhenchun,ZHU Li,YE Yueming,et al.Extraction and stack imaging of angle domain common image gathers[J].Geophysical Prospecting for Petroleum,2008,47(6):567-572.
[25] 张敏,李振春,叶月明,等.基于双平方根算子的保幅角度域成像[J].中国石油大学学报,2011,35(2):45-50.ZHANG Min,LI Zhenchun,YE Yueming,et al.Amplitude preserved imaging based on double sqraretoor wave equation in angle domain[J].Journal of China University of Petroleum,2011,35(2):45-50.
[26] Tang B,Xu S,Zhang Y.3D angle gathers from plane-wave reverse time migration[J].Geophysics,2013,78(2):117-123.
[27] 张广智,常德宽,王一惠,等.波动方程叠前深度偏移角度道集求取方法[J].石油地球物理勘探,2016,51(3):529-536.ZHANG Guangzhi,CHANG Dekuan,WANG Yihui,et al.Angle domain common image gather calculation based on wave equation prestack depth migration[J].Oil Geophysical Prospecting,2016,51(3):529-536.
[28] 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.
[29] Thomesen L.Weak elastic anisotropy[J].Geophysics,1986,51(6):1954-1966.
[30] Zhang K,Li Z C,Zeng T S,et al.Residual curvature migration velocity analysis for angle domain common imaging gathers[J].Applied Geophysics,2010,7(1):49-56.
[2] 王赟,杨顶辉,殷长春,等.各向异性地球物理与矢量场[J].科学通报,2017,62(23):2595-2605.WANG Yun,YANG Dinghui,YIN Changchun,et al.Anisotropic geophysics and vector field[J].Chinese Science Bulletin,2017,62(23):2595-2605.
[3] 王咸彬.TTI各向异性逆时偏移技术[J].石油物探,2017,56(4):534-542.WANG Xianbin.Anisotropic reverse time migration technique in TTI media and its application[J].Geophysical Prospecting for Petroleun,2017,56(4):534-542.
[4] Alkhalifah T.An acoustic wave equation for aniso-tropic media[J].Geophysics,2000,65(4):1239-1250.
[5] 吴国忱,梁锴,王华忠.VTI介质qP波广义高阶屏单程传播算子[J].石油地球物理勘探,2007,42(6):640-650.WU Guochen,LIANG Kai,WANG Huazhong.High order one way generalized screen propagation operator of qP wave in VTI medium[J].Oil Geophysical Prospecting,2007,42(6):640-650.
[6] 韩建光,王赟,张晓波,等.VTI介质高斯束叠前深度偏移[J].石油地球物理勘探,2015,50(2):267-273.HAN Jianguang,WANG Yun,ZHANG Xiaobo,et al.Gaussian beam prestack depth migration in VTI media[J].Oil Geophysical Prospecting,2015,50(2):267-273.
[7] 韩建光,王赟,陈传绪,等.二维各向异性多波高斯束叠前深度偏移[J].地球物理学进展,2017,32(3):1130-1139.HAN Jianguang,WANG Yun,CHEN Chuanxu,et al.Multiwave Gaussian beam prestack depth migration for 2D anisotropic media[J].Progress in Geophysics,2017,32(3):1130-1139.
[8] 刘礼农,高红伟,刘洪,等.三维VTI介质中波动方程深度偏移的最优分裂Fourier方法[J].地球物理学报,2005,48(2):406-414.LIU Linong,GAO Hongwei,LIU Hong,et al.Wave equation depth migration with optimum split step Fourier method in 3D VTI media[J].Chinese Journal of Geophysics,2005,48(2):406-414.
[9] 刘礼农,张剑锋.三维各向异性介质中的波动方程叠前深度偏移方法[J].地球物理学报,2011,54(11):2906-2915.LIU Linong,ZHANG Jianfeng.Wave equation prestack depth migration method in 3D VTI media[J].Chinese Journal of Geophysics,2011,54(11):2906-2915.
[10] 程玖兵,康玮,王腾飞.各向异性介质qP波传播描述Ⅰ:伪纯模式波动方程[J].地球物理学报,2013,56(10):3474-3486.CHENG Jiubing,KANG Wei,WANG Tengfei.Description of qP wave propagation in anisotropic media,Part Ⅰ:Pseudo-pure-mode wave equation[J].Chinese Journal of Geophysics,2013,56(10):3474-3486.
[11] 程玖兵,陈茂根,王腾飞,等.各向异性介质qP波传播描述Ⅱ:分离纯模式标量波[J].地球物理学报,2014,57(10):3389-3401.CHENG Jiubing,CHEN Maogen,WANG Tenfei,et al.Description of qP wave propagation in anisotropic media,Part Ⅱ:Separation of pure-mode scalar wave[J].Chinese Journal of Geophysics ,2014,57(10):3389-3401.
[12] Sun X D,Ge Z H,Li Z C,et al.The stability problem of reverse time migration for viscoacoustic VTI media[J].Applied Geophysics,2016,13(4):608-613.
[13] Zhang J M,He B S,Tang H G.Pure quasi P wave equation and numerical solution in 3D TTI media [J].Applied Geophysics,2017,14(1):125-132.
[14] Hua B ,Lencrerot R ,Williamson P ,et al.High-order and high-accuracy 3D Fourier finite difference depth migration with an optimally reduced coefficient table for the tilted transversely isotropic media[C].SEG Technical Program Expanded Abstracts,2013,32:3794-3798.
[15] 黄建平,朱峰,李振春,等.VTI介质FFD叠前深度偏移成像方法[J].石油地球物理勘探,2017,52(3):491-501.HUANG Jianping,ZHU Feng,LI Zhenchun,et al.FFD prestack depth migration imaging method for VTI medium[J].Oil Geophysical Prospecting,2017,52(3):491-501.
[16] 朱峰,黄建平,李振春.黏声VTI介质傅里叶有限差分叠前深度偏移[J].石油地球物理勘探,2017,52(5):956-966.ZHU Feng,HUANG Jianping,LI Zhenchun.FFD prestack depth migration for visco-acoustic VTI me-dium[J].Oil Geophysical Prospecting,2017,52(5):956-966.
[17] Hoop D E,Le Rousseau J H,Wu R S.Generalization of the phase approximation for the scattering of acoustic waves[J].Wave Motion,2000,31(1):43-70.
[18] Xu S,Chauris H,Lambare G,et al.Common angle migration:A strategy for imaging complex media[J].Geophysics,2001,66(6):1877-1894.
[19] Stork C,Symes W.Kinematic artifacts in prestack depth migration[J].Geophysics,2004,69(2):562-575.
[20] Xie X,Wu R.Extracting angle domain information from migration wave field[C].SEG Technical Program Expanded Abstracts,2002,21:1360-1363.
[21] James E,Rickett J E,Save P C.Offset and angle domain common image point gather for shot profile migration[J].Geophysics,2002,67(3):883-889.
[22] Save P,Fomel S.Angle domain common image gathers by wave field continuation[J].Geophysics,2003,68(3):1065-1074.
[23] Biondi B.Angle domain common image gathers from anisotropic migration[J].Geophysics,2007,72(2):S81-91.
[24] 李振春,朱莉,叶月明,等.角度域共成像点道集的提取与叠加成像[J].石油物探,2008,47(6):567-572.LI Zhenchun,ZHU Li,YE Yueming,et al.Extraction and stack imaging of angle domain common image gathers[J].Geophysical Prospecting for Petroleum,2008,47(6):567-572.
[25] 张敏,李振春,叶月明,等.基于双平方根算子的保幅角度域成像[J].中国石油大学学报,2011,35(2):45-50.ZHANG Min,LI Zhenchun,YE Yueming,et al.Amplitude preserved imaging based on double sqraretoor wave equation in angle domain[J].Journal of China University of Petroleum,2011,35(2):45-50.
[26] Tang B,Xu S,Zhang Y.3D angle gathers from plane-wave reverse time migration[J].Geophysics,2013,78(2):117-123.
[27] 张广智,常德宽,王一惠,等.波动方程叠前深度偏移角度道集求取方法[J].石油地球物理勘探,2016,51(3):529-536.ZHANG Guangzhi,CHANG Dekuan,WANG Yihui,et al.Angle domain common image gather calculation based on wave equation prestack depth migration[J].Oil Geophysical Prospecting,2016,51(3):529-536.
[28] 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.
[29] Thomesen L.Weak elastic anisotropy[J].Geophysics,1986,51(6):1954-1966.
[30] Zhang K,Li Z C,Zeng T S,et al.Residual curvature migration velocity analysis for angle domain common imaging gathers[J].Applied Geophysics,2010,7(1):49-56.
© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |