频率域海洋可控源电磁垂直各向异性三维反演
|
摘要
地层宏观电性各向异性会对可控源电磁响应产生重要影响.由于海底地层电性结构常表现为电导率各向异性,若仅对海洋可控源电磁(MCSEM)数据进行常规各向同性反演,有可能无法获得准确的反演解释结果,从而削弱MCSEM技术的可靠性.本文实现了电导率垂直各向异性(VTI)条件下频率域海洋可控源电磁数据三维反演算法.其中,三维正演采用基于二次场控制方程的交错网格有限体积法,并利用直接矩阵分解技术来求解离散所得的大型线性方程组,有利于快速计算多场源的响应.反演采用具有近似二次收敛性的高斯牛顿算法对目标函数进行最优化.最后,对具有VTI电性各向异性特征的盐丘构造模型的MCSEM合成数据分别进行了电导率各向同性和垂直各向异性三维反演,结果表明:各向同性三维反演算法无法对受VTI介质影响的MCSEM数据进行正确的反演解释,而垂直各向异性三维反演能够获得更为可靠的地下电阻率结构和异常体分布,展现出对海底电性各向异性结构更为优良的反演解释能力.
Electrical anisotropy of geologic formations has a significant impact on controlled source electromagnetic(CSEM)field responses.It is now well recognized that sedimentary formations in the marine environment are usually characterized by electrical anisotropy due to strong sedimentation.In the presence of such electrical anisotropy,the interpretation of marine CSEM data based on the assumption of isotropic media may produce misleading resistivity images,which will undermine the power of MCSEM technique.To solve this problem,we develop an efficient three-dimensional(3 D)anisotropic inversion algorithm for marine CSEM data affected by structures with vertical transverse isotropy(VTI).The forward engine is based on the scattering-field formulation to mitigate the numerical singularity in the vicinity of the transmitters,and employs a direct matrix factorization method to solve the system of linear equations arising from finite volume discretization.The direct solver facilitates the reuse of the matrix factorization,which makes the solutions for multiple transmitters with little additionaleffort.The inverse algorithm is based on the Gauss-Newton method with a quasi-quadratic convergence rate,which reduces the number of expensive matrix factorization required.Finally,numerical experiments on synthetic marine CSEM data show that 3 Danisotropic inversion can produce more reliable resistivity images,demonstrating better interpretation capacity than conventional isotropic inversion of marine CSEM data in the presence of electrical anisotropy.
Electrical anisotropy of geologic formations has a significant impact on controlled source electromagnetic(CSEM)field responses.It is now well recognized that sedimentary formations in the marine environment are usually characterized by electrical anisotropy due to strong sedimentation.In the presence of such electrical anisotropy,the interpretation of marine CSEM data based on the assumption of isotropic media may produce misleading resistivity images,which will undermine the power of MCSEM technique.To solve this problem,we develop an efficient three-dimensional(3 D)anisotropic inversion algorithm for marine CSEM data affected by structures with vertical transverse isotropy(VTI).The forward engine is based on the scattering-field formulation to mitigate the numerical singularity in the vicinity of the transmitters,and employs a direct matrix factorization method to solve the system of linear equations arising from finite volume discretization.The direct solver facilitates the reuse of the matrix factorization,which makes the solutions for multiple transmitters with little additionaleffort.The inverse algorithm is based on the Gauss-Newton method with a quasi-quadratic convergence rate,which reduces the number of expensive matrix factorization required.Finally,numerical experiments on synthetic marine CSEM data show that 3 Danisotropic inversion can produce more reliable resistivity images,demonstrating better interpretation capacity than conventional isotropic inversion of marine CSEM data in the presence of electrical anisotropy.
引文
Amestoy P R,Guermouche A,L′Excellent J Y,et al.2006.Hybrid scheduling for the parallel solution of linear systems.Parallel Computing,32(2):136-156.
Aminzadeh F,Brac J,Kuntz T.1997.3-D salt and overthrust models.∥67th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts.
Anderson B,Bryant I,Luling M,et al.1994.Oilfield anisotropy:Its origins and electrical characteristics.Oilfield Review,6(4):48-56.
Brown V,Hoversten M,Key K,et al.2012.Resolution of reservoir scale electrical anisotropy from marine CSEM data.Geophysics,77(2):E147-E158.
Chen H B,Li T L,Xiong B,et al.2017.Finite-element modeling of3D MCSEM in arbitrarily anisotropic medium using potentials on unstructured grids.Chinese Journal of Geophysics(in Chinese),60(8):3254-3263,doi:10.6038/cjg20170830.
Clavaud J B.2008.Intrinsic electrical anisotropy of shale:The effect of compaction.Petrophysics,49(3):243-260.
Commer M,Newman G A.2008.New advances in three-dimensional controlled-source electromagnetic inversion.Geophysical Journal International,172(2):513-535.
Constable S.2010.Ten years of marine CSEM for hydrocarbon exploration.Geophysics,75(5):75A67-75A81.
Han B,Hu X Y,He Z X,et al.2012.Mathematical classification of magnetotelluric inversion methods.Oil Geophysical Prospecting(in Chinese),47(1):177-188.
Han B,Hu X Y,Huang Y F,et al.2015.3-D frequency-domain CSEM modeling using aparallel direct solver.Chinese Journal of Geophysics(in Chinese),58(8):2812-2826,doi:10.6038/cjg20150816.
Hunziker J,Thorbecke J,Slob E.2014.The electromagnetic response in a layered vertical transverse isotropic medium:Anew look at an old problem.Geophysics,80(1):F1-F18.
Jahandari H,Farquharson C G.2017.3-D minimum-structure inversion of magnetotelluric data using the finite-element method and tetrahedral grids.Geophysical Journal International,211(2):1189-1205.
Key K.2016.MARE2DEM:A 2-D inversion code for controlledsource electromagnetic and magnetotelluric data.Geophysical Journal International,207(1):571-588.
Leveille J P,Jones I F,Zhou Z Z,et al.2011.Subsalt imaging for exploration,production,and development:A review.Geophysics,76(5):WB3-WB20.
Li Y G,Dai S K.2011.Finite element modelling of marine controlledsource electromagnetic responses in two-dimensional dipping anisotropic conductivity structures.Geophysical Journal International,185(2):622-636.
Luo M,Li Y G,Li G.2016.Frequency-domain inversion of marine CSEM data in one-dimensional vertically anisotropic structures.Chinese Journal of Geophysics(in Chinese),59(11):4349-4359,doi:10.6038/cjg20161134.
Masnaghetti L,Ceci F.2010.Analysis of the sensitivity to anisotropy of CSEM data using 2.5D modeling and inversion.∥80th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts.
Mohamad S A,Lorenz L,Hoong L T,et al.2010.A practical example why anisotropy matters:A CSEM case study from south east Asia.∥80th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts.
Newman G A,Commer M,Carazzone J J.2010.Imaging CSEMdata in the presence of electrical anisotropy.Geophysics,75(2):F51-F61.
Nocedal J,Wright S.1999.Numerical Optimization.New York,USA:Springer-Verlag.
Oldenburg D W,Haber E,Shekhtman R.2012.Three dimensional inversion of multisource time domain electromagnetic data.Geophysics,78(1):E47-E57.
Peng R H,Hu X Y,Han B.2016a.3Dinversion of frequencydomain CSEM data based on Gauss-Newton optimization.Chinese Journal of Geophysics(in Chinese),59(9):3470-3481,doi:10.6038/cjg20160929.
Peng R H,Hu X Y,Han B,et al.2016b.3Dfrequency-domain CSEM forward modeling based on the mimetic finite-volume method.Chinese Journal of Geophysics(in Chinese),59(10):3927-3939,doi:10.6038/cjg20161036.
Ramananjaona C,MacGregor L,Andréis.2011.Sensitivity and inversion of marine electromagnetic data in a vertically anisotropic stratified earth.Geophysical Prospecting,59(2):341-360.
Sasaki Y.2013.Resolution of shallow and deep marine CSEM data inferred from anisotropic 3Dinversion.∥83rd Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts.
Streich R.2009.3Dfinite-difference frequency-domain modeling of controlled-source electromagnetic data:Direct solution and optimization for high accuracy.Geophysics,74(5):F95-F105.
Tikhonov A N,Arsenin V.1977.Solutions of Ill-Posed Problems.Washington,D C,USA:John Wiley and Sons.
Um E S,Commer M,Newman G A.2014.A strategy for coupled3Dimaging of large-scale seismic and electromagnetic data sets:Application to subsalt imaging.Geophysics,79(3):ID1-ID13.
Weiss C J,Constable S C.2006.Mapping thin resistors and hydrocarbons with marine EM methods,Part II-Modeling and analysis in 3D.Geophysics,71(6):G321-G332.
Wiik T,L9seth L O,Usrin B,et al.2011.TIV contrast source inversion of mCSEM data.Geophysics,76(1):F65-F76.
Yan F Y,Han D H,Yao Q L,et al.2014.Seismic velocities of halite salt:Anisotropy,dispersion,temperature and stress effects.∥84th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts.
Yin C C,Ben F,Liu Y H,et al.2014.MCSEM 3D modeling for arbitrarily anisotropic media.Chinese Journal of Geophysics(in Chinese),57(12):4110-4122,doi:10.6038/cjg20141222.
Yu L M,Edwards R.1992.The detection of lateral anisotropy of the ocean floor by electromagnetic methods.Geophysical Journal International,108(2):433-441.
Zhao N,Wang X B,Qin C,et al.2017.3Dfrequency-domain MCSEM constrained inversion in VTI media.Chinese Journal of Geophysics(in Chinese),60(5):1946-1954,doi:10.6038/cjg20170527.
Zhou J M,Zhang Y,Wang H N,et al.2014.Efficient simulation of three-dimensional marine controlled-source electromagnetic response in anisotropic formation by means of coupled potential finite volume method.Acta Physica Sinica(in Chinese),63(15):159101,doi:10.7498/aps.63.159101.
陈汉波,李桐林,熊彬等.2017.基于Coulomb规范势的电导率呈任意各向异性海洋可控源电磁三维非结构化有限元数值模拟.地球物理学报,60(8):3254-3263,doi:10.6038/cjg20170830.
韩波,胡祥云,何展翔等.2012.大地电磁反演方法的数学分类.石油地球物理勘探,47(1):177-188.
韩波,胡祥云,黄一凡等.2015.基于并行化直接解法的频率域可控源电磁三维正演.地球物理学报,58(8):2812-2826,doi:10.6038/cjg20150816.
罗鸣,李予国,李刚.2016.一维垂直各向异性介质频率域海洋可控源电磁资料反演方法.地球物理学报,59(11):4349-4359,doi:10.6038/cjg20161134.
彭荣华,胡祥云,韩波.2016a.基于高斯牛顿法的频率域可控源电磁三维反演研究.地球物理学报,59(9):3470-3481,doi:10.6038/cjg20160929.
彭荣华,胡祥云,韩波等.2016b.基于拟态有限体积法的频率域可控源三维正演计算.地球物理学报,59(10):3927-3939,doi:10.6038/cjg20161036.
殷长春,贲放,刘云鹤等.2014.三维任意各向异性介质中海洋可控源电磁法正演研究.地球物理学报,57(12):4110-4122,doi:10.6038/cjg20141222.
赵宁,王绪本,秦策等.2017.基于VTI各向异性介质的频率域海洋可控源电磁三维约束反演.地球物理学报,60(5):1946-1954,doi:10.6038/cjg20170527.
周建美,张烨,汪宏年等.2014.耦合势有限体积法高效模拟各向异性地层中海洋可控源的三维电磁响应.物理学报,63(15):15901,doi:10.7498/aps.63.159101.
Aminzadeh F,Brac J,Kuntz T.1997.3-D salt and overthrust models.∥67th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts.
Anderson B,Bryant I,Luling M,et al.1994.Oilfield anisotropy:Its origins and electrical characteristics.Oilfield Review,6(4):48-56.
Brown V,Hoversten M,Key K,et al.2012.Resolution of reservoir scale electrical anisotropy from marine CSEM data.Geophysics,77(2):E147-E158.
Chen H B,Li T L,Xiong B,et al.2017.Finite-element modeling of3D MCSEM in arbitrarily anisotropic medium using potentials on unstructured grids.Chinese Journal of Geophysics(in Chinese),60(8):3254-3263,doi:10.6038/cjg20170830.
Clavaud J B.2008.Intrinsic electrical anisotropy of shale:The effect of compaction.Petrophysics,49(3):243-260.
Commer M,Newman G A.2008.New advances in three-dimensional controlled-source electromagnetic inversion.Geophysical Journal International,172(2):513-535.
Constable S.2010.Ten years of marine CSEM for hydrocarbon exploration.Geophysics,75(5):75A67-75A81.
Han B,Hu X Y,He Z X,et al.2012.Mathematical classification of magnetotelluric inversion methods.Oil Geophysical Prospecting(in Chinese),47(1):177-188.
Han B,Hu X Y,Huang Y F,et al.2015.3-D frequency-domain CSEM modeling using aparallel direct solver.Chinese Journal of Geophysics(in Chinese),58(8):2812-2826,doi:10.6038/cjg20150816.
Hunziker J,Thorbecke J,Slob E.2014.The electromagnetic response in a layered vertical transverse isotropic medium:Anew look at an old problem.Geophysics,80(1):F1-F18.
Jahandari H,Farquharson C G.2017.3-D minimum-structure inversion of magnetotelluric data using the finite-element method and tetrahedral grids.Geophysical Journal International,211(2):1189-1205.
Key K.2016.MARE2DEM:A 2-D inversion code for controlledsource electromagnetic and magnetotelluric data.Geophysical Journal International,207(1):571-588.
Leveille J P,Jones I F,Zhou Z Z,et al.2011.Subsalt imaging for exploration,production,and development:A review.Geophysics,76(5):WB3-WB20.
Li Y G,Dai S K.2011.Finite element modelling of marine controlledsource electromagnetic responses in two-dimensional dipping anisotropic conductivity structures.Geophysical Journal International,185(2):622-636.
Luo M,Li Y G,Li G.2016.Frequency-domain inversion of marine CSEM data in one-dimensional vertically anisotropic structures.Chinese Journal of Geophysics(in Chinese),59(11):4349-4359,doi:10.6038/cjg20161134.
Masnaghetti L,Ceci F.2010.Analysis of the sensitivity to anisotropy of CSEM data using 2.5D modeling and inversion.∥80th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts.
Mohamad S A,Lorenz L,Hoong L T,et al.2010.A practical example why anisotropy matters:A CSEM case study from south east Asia.∥80th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts.
Newman G A,Commer M,Carazzone J J.2010.Imaging CSEMdata in the presence of electrical anisotropy.Geophysics,75(2):F51-F61.
Nocedal J,Wright S.1999.Numerical Optimization.New York,USA:Springer-Verlag.
Oldenburg D W,Haber E,Shekhtman R.2012.Three dimensional inversion of multisource time domain electromagnetic data.Geophysics,78(1):E47-E57.
Peng R H,Hu X Y,Han B.2016a.3Dinversion of frequencydomain CSEM data based on Gauss-Newton optimization.Chinese Journal of Geophysics(in Chinese),59(9):3470-3481,doi:10.6038/cjg20160929.
Peng R H,Hu X Y,Han B,et al.2016b.3Dfrequency-domain CSEM forward modeling based on the mimetic finite-volume method.Chinese Journal of Geophysics(in Chinese),59(10):3927-3939,doi:10.6038/cjg20161036.
Ramananjaona C,MacGregor L,Andréis.2011.Sensitivity and inversion of marine electromagnetic data in a vertically anisotropic stratified earth.Geophysical Prospecting,59(2):341-360.
Sasaki Y.2013.Resolution of shallow and deep marine CSEM data inferred from anisotropic 3Dinversion.∥83rd Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts.
Streich R.2009.3Dfinite-difference frequency-domain modeling of controlled-source electromagnetic data:Direct solution and optimization for high accuracy.Geophysics,74(5):F95-F105.
Tikhonov A N,Arsenin V.1977.Solutions of Ill-Posed Problems.Washington,D C,USA:John Wiley and Sons.
Um E S,Commer M,Newman G A.2014.A strategy for coupled3Dimaging of large-scale seismic and electromagnetic data sets:Application to subsalt imaging.Geophysics,79(3):ID1-ID13.
Weiss C J,Constable S C.2006.Mapping thin resistors and hydrocarbons with marine EM methods,Part II-Modeling and analysis in 3D.Geophysics,71(6):G321-G332.
Wiik T,L9seth L O,Usrin B,et al.2011.TIV contrast source inversion of mCSEM data.Geophysics,76(1):F65-F76.
Yan F Y,Han D H,Yao Q L,et al.2014.Seismic velocities of halite salt:Anisotropy,dispersion,temperature and stress effects.∥84th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts.
Yin C C,Ben F,Liu Y H,et al.2014.MCSEM 3D modeling for arbitrarily anisotropic media.Chinese Journal of Geophysics(in Chinese),57(12):4110-4122,doi:10.6038/cjg20141222.
Yu L M,Edwards R.1992.The detection of lateral anisotropy of the ocean floor by electromagnetic methods.Geophysical Journal International,108(2):433-441.
Zhao N,Wang X B,Qin C,et al.2017.3Dfrequency-domain MCSEM constrained inversion in VTI media.Chinese Journal of Geophysics(in Chinese),60(5):1946-1954,doi:10.6038/cjg20170527.
Zhou J M,Zhang Y,Wang H N,et al.2014.Efficient simulation of three-dimensional marine controlled-source electromagnetic response in anisotropic formation by means of coupled potential finite volume method.Acta Physica Sinica(in Chinese),63(15):159101,doi:10.7498/aps.63.159101.
陈汉波,李桐林,熊彬等.2017.基于Coulomb规范势的电导率呈任意各向异性海洋可控源电磁三维非结构化有限元数值模拟.地球物理学报,60(8):3254-3263,doi:10.6038/cjg20170830.
韩波,胡祥云,何展翔等.2012.大地电磁反演方法的数学分类.石油地球物理勘探,47(1):177-188.
韩波,胡祥云,黄一凡等.2015.基于并行化直接解法的频率域可控源电磁三维正演.地球物理学报,58(8):2812-2826,doi:10.6038/cjg20150816.
罗鸣,李予国,李刚.2016.一维垂直各向异性介质频率域海洋可控源电磁资料反演方法.地球物理学报,59(11):4349-4359,doi:10.6038/cjg20161134.
彭荣华,胡祥云,韩波.2016a.基于高斯牛顿法的频率域可控源电磁三维反演研究.地球物理学报,59(9):3470-3481,doi:10.6038/cjg20160929.
彭荣华,胡祥云,韩波等.2016b.基于拟态有限体积法的频率域可控源三维正演计算.地球物理学报,59(10):3927-3939,doi:10.6038/cjg20161036.
殷长春,贲放,刘云鹤等.2014.三维任意各向异性介质中海洋可控源电磁法正演研究.地球物理学报,57(12):4110-4122,doi:10.6038/cjg20141222.
赵宁,王绪本,秦策等.2017.基于VTI各向异性介质的频率域海洋可控源电磁三维约束反演.地球物理学报,60(5):1946-1954,doi:10.6038/cjg20170527.
周建美,张烨,汪宏年等.2014.耦合势有限体积法高效模拟各向异性地层中海洋可控源的三维电磁响应.物理学报,63(15):15901,doi:10.7498/aps.63.159101.