磁化率对大地电磁响应的影响及其提取方法
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摘要
在电磁探测理论中,电导率和磁导率是两个重要的岩石物性参数。在磁性较强的地区进行大地电磁探测工作时,电磁场信号必然受到介质磁性的影响。将磁化率参数引入到二维大地电磁正演理论中,实现了含磁化率的大地电磁有限单元法数值模拟。建立棱柱体模型计算并分析了磁化率参数对大地电磁的电场、磁场、视电阻率及相位等参数的影响。数值模拟结果表明:高磁性介质导致电场升高,磁场降低,视电阻率增大,相位复杂变化,且随着磁性物质的增多或磁化率的增大,这种影响逐渐变大。引入电导率、磁化率光滑约束与磁化率对数约束,采用改进的特别快速模拟退火法实现了电阻率、磁化率参数一维同时反演。对K型、H型中间层高磁地电模型进行反演试算,反演结果良好。该研究为在高磁性地区开展大地电磁工作提供了基础,对实现"第二找矿空间"内的矿产勘探,具有一定的意义。
In electromagnetic theory,conductivity and permeability are two important petrophysical parameters. The electromagnetic signal will inevitably be affected by the magnetic properties of the media in MT detection where magnetism is strong.The authors made the numerical simulation of the electromagnetic finite element method with magnetic susceptibility by introducing the magnetic susceptibility parameter into the two-dimensional MT forward theory.Prism model was established for calculation and analysis of the influence of the magnetic susceptibility parameters on the electric field,magnetic field,MT apparent resistivity and phase parameters.The numerical simulation results show that the high magnetic medium results in increasing the electric field,reducing the magnetic field,increasing the apparent resistivity,and complex changes of phase and,with the increase of the magnetic substance or the increase of the magnetization rate,the effect gradually becomes larger.The inversion results of geoelectric model with high magnetic middle layer are good.The results obtained by the authors provide a theoretical basis for the MT work in the high magnetic area and also have a certain significance for conducting the mineral prospecting in " the second space".
In electromagnetic theory,conductivity and permeability are two important petrophysical parameters. The electromagnetic signal will inevitably be affected by the magnetic properties of the media in MT detection where magnetism is strong.The authors made the numerical simulation of the electromagnetic finite element method with magnetic susceptibility by introducing the magnetic susceptibility parameter into the two-dimensional MT forward theory.Prism model was established for calculation and analysis of the influence of the magnetic susceptibility parameters on the electric field,magnetic field,MT apparent resistivity and phase parameters.The numerical simulation results show that the high magnetic medium results in increasing the electric field,reducing the magnetic field,increasing the apparent resistivity,and complex changes of phase and,with the increase of the magnetic substance or the increase of the magnetization rate,the effect gradually becomes larger.The inversion results of geoelectric model with high magnetic middle layer are good.The results obtained by the authors provide a theoretical basis for the MT work in the high magnetic area and also have a certain significance for conducting the mineral prospecting in " the second space".
引文
[1]魏文博.我国大地电磁测深新进展及瞻望[J].地球物理学进展,2002,17(2):245-254.
[2]李爱勇,柳建新,朱春生,等.大地电磁测深在桂中坳陷油气勘探中的应用[J].物探与化探,2012,36(1):8-12.
[3]姚大为,朱威,王大勇,等.音频大地电磁法在武山外围深部勘查中的应用[J].物探与化探,2015,39(1):100-103.
[4]杨学明,苏永军,杜东,等.音频大地电磁法在海水入侵动态监测中的应用[J].物探与化探,2013,37(2):301-305.
[5]武毅,封绍武,王亚清.应用大地电磁法TE、TM模式勘查构造裂隙水[J].物探与化探,2011,35(3):329-332.
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[10]刘应冬,谭捍东,宋文杰.磁化率参数对大地电磁响应的影响研究[J].地球物理学进展,2014,29(5):2040-2046.
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[12]Beard L P,Nyquist J E.Simultaneous inversion of airborne electromagnetic date for resistivity and magnetic permeability[J].Geophysics,1998,63(5),1556-1564.
[13]Zhang Z Y,Oldenburg D W.Simultaneous reconstruction of 1-D susceptibility and conductivity from electromagnetic date[J].Geophysics,1999(64):33-47.
[14]Farquharson C G,Oldenburg D W.Simultaneous one-dimensional inversion of electromagnetic loop-loop data for both magnetic susceptibility and electrical conductivity[J].Geophysics,2003,68(6):1857-1869.
[15]曹俊兴,李学民,贺振华.考虑磁参数MT反演[C]//第六届中国国际地球电磁学术讨论会,2003.
[16]滕吉文.强化开展地壳内部第二深度空间金属矿产资源地球物理找矿、勘探和开发[J].地质通报,2006,25(7):767-771.
[17]管志宁.地磁场与磁力勘探[M].北京:地质出版社,2005.
[18]朴化荣.电磁探测法原理[M].北京:地质出版社,1990.
[19]李貅,冯兵.应用地球物理基础教程(上)[M].西安:陕西人民教育出版社,2003.
[20]徐世浙.地球物理中的有限单元法[M].北京:科学出版社,1994.
[21]王珺璐,刘明文,李荡,等.基于Cole-Cole复电阻率模型的线源可控源有限元数值模拟[J].物探化探计算技术,2015,37(1):32-39.
[22]冯兵,王珺璐,王玉,等.利用CSAMT电磁场响应提取激电效应的方法初探[J].地球物理学进展,2013,28(4):2116-2122.
[23]于鹏,王家林,吴健生,等.重力与地震资料的模拟退火约束联合反演[J].地球物理学报,2007,50(2):529-538.
[24]师学明,王家映.地球物理资料非线性反演方法讲座(三)模拟退火法[J].工程地球物理学报,2007,4(3):165-174.
[25]师学明,王家映.一维层状介质大地电磁模拟退火反演法[J].工程地球物理学报,1998,23(5):542-545.
[26]杨辉,王家林,吴健生,等.大地电磁与地震资料仿真退火约束联合反演[J].地球物理学报,2002,45(5):723-734.
[27]陈华根,吴健生,王家林.改进的重力模拟退火反演研究[J].吉林大学学报:地球科学版,2002,32(3):294-298、303.
[28]李帝铨,王光杰,底青云,等.基于遗传算法的CSAMT最小构造反演[J].地球物理学报,2008,51(4):1234-1245.
[29]汤井田,张林成,肖晓.基于频点CSAMT一维最小构造反演[J].物探化探计算技术,2011,33(6):577-581,571.
[30]Li Y G,Oldenburg D W.Fast inversion of large-scale magnetic data using wavelet transforms[J].Geophysics,2003,152(2):251-265.
[2]李爱勇,柳建新,朱春生,等.大地电磁测深在桂中坳陷油气勘探中的应用[J].物探与化探,2012,36(1):8-12.
[3]姚大为,朱威,王大勇,等.音频大地电磁法在武山外围深部勘查中的应用[J].物探与化探,2015,39(1):100-103.
[4]杨学明,苏永军,杜东,等.音频大地电磁法在海水入侵动态监测中的应用[J].物探与化探,2013,37(2):301-305.
[5]武毅,封绍武,王亚清.应用大地电磁法TE、TM模式勘查构造裂隙水[J].物探与化探,2011,35(3):329-332.
[6]米萨克N纳比吉安.勘查地球物理电磁法[M].赵经祥,译.北京:地质出版社,1992.
[7]Fraser D C.Magnetite ore tonnage estimates from an aerial electromagnetic survey[J].Geoexploration,1973(11):97-105.
[8]Thomas L.Electromagnetic sounding with susceptibility among the model parameters[J].Geophysics,1997,42(1):92-96.
[9]李学民,曹俊兴.磁化率对大地电磁响应的影响研究[J].地球物理学报,2005,48(4):947-950.
[10]刘应冬,谭捍东,宋文杰.磁化率参数对大地电磁响应的影响研究[J].地球物理学进展,2014,29(5):2040-2046.
[11]Zhang Z Y,Oldenburg D W.Recovering magnetic susceptibility from electromagnetic date over a one-dimensional earth[J].Gocphys.J.Int.1997(130):422-434.
[12]Beard L P,Nyquist J E.Simultaneous inversion of airborne electromagnetic date for resistivity and magnetic permeability[J].Geophysics,1998,63(5),1556-1564.
[13]Zhang Z Y,Oldenburg D W.Simultaneous reconstruction of 1-D susceptibility and conductivity from electromagnetic date[J].Geophysics,1999(64):33-47.
[14]Farquharson C G,Oldenburg D W.Simultaneous one-dimensional inversion of electromagnetic loop-loop data for both magnetic susceptibility and electrical conductivity[J].Geophysics,2003,68(6):1857-1869.
[15]曹俊兴,李学民,贺振华.考虑磁参数MT反演[C]//第六届中国国际地球电磁学术讨论会,2003.
[16]滕吉文.强化开展地壳内部第二深度空间金属矿产资源地球物理找矿、勘探和开发[J].地质通报,2006,25(7):767-771.
[17]管志宁.地磁场与磁力勘探[M].北京:地质出版社,2005.
[18]朴化荣.电磁探测法原理[M].北京:地质出版社,1990.
[19]李貅,冯兵.应用地球物理基础教程(上)[M].西安:陕西人民教育出版社,2003.
[20]徐世浙.地球物理中的有限单元法[M].北京:科学出版社,1994.
[21]王珺璐,刘明文,李荡,等.基于Cole-Cole复电阻率模型的线源可控源有限元数值模拟[J].物探化探计算技术,2015,37(1):32-39.
[22]冯兵,王珺璐,王玉,等.利用CSAMT电磁场响应提取激电效应的方法初探[J].地球物理学进展,2013,28(4):2116-2122.
[23]于鹏,王家林,吴健生,等.重力与地震资料的模拟退火约束联合反演[J].地球物理学报,2007,50(2):529-538.
[24]师学明,王家映.地球物理资料非线性反演方法讲座(三)模拟退火法[J].工程地球物理学报,2007,4(3):165-174.
[25]师学明,王家映.一维层状介质大地电磁模拟退火反演法[J].工程地球物理学报,1998,23(5):542-545.
[26]杨辉,王家林,吴健生,等.大地电磁与地震资料仿真退火约束联合反演[J].地球物理学报,2002,45(5):723-734.
[27]陈华根,吴健生,王家林.改进的重力模拟退火反演研究[J].吉林大学学报:地球科学版,2002,32(3):294-298、303.
[28]李帝铨,王光杰,底青云,等.基于遗传算法的CSAMT最小构造反演[J].地球物理学报,2008,51(4):1234-1245.
[29]汤井田,张林成,肖晓.基于频点CSAMT一维最小构造反演[J].物探化探计算技术,2011,33(6):577-581,571.
[30]Li Y G,Oldenburg D W.Fast inversion of large-scale magnetic data using wavelet transforms[J].Geophysics,2003,152(2):251-265.