电偶源瞬变电磁测深浅层探测问题的理论研究
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摘要
瞬变电磁法是电磁法勘探中极为常用的一种物探方法。本文针对目前研究较少的水平电偶源瞬变电磁测深法进行正演计算研究。首先由场论推导出均匀半空间及各向同性水平层状大地的垂直磁场,通过快速汉克尔变换实现频率域的正演计算,再通过G-S变换,实现从频率域到时间域的转换计算。通过迭代算法得出频率域的全区视电阻率,在时间域中由于有关断电流产生的关断效应,作者则提出先计算带有关断效应的时间域二次场,然后通过全区搜索算法得出全区视电阻率,从而实现关断电流的校正。通过计算表明,对于多地层而言,中间层会受到紧邻地层的影响,但是得出的曲线基本能反映地下的电性结构。
The transient electromagnetic method is one of the commonly used electromagnetic method in the geophysical exploration. In this paper,the author focus on the forward calculation of the transient electromagnetic method with electric dipoles which is less discussed nowadays. First, let the field theory deduces the homogeneous half-space and isotropic horizontal layered earth's vertical magnetic field, through the fast hankel transformation to realize frequency domain forward calculation, then through the G-S transformation to realize from the frequency domain to the time domain conversion. Through the iterative algorithm to obtained the apparent resistivity in the frequency domain. Since the turn-off effect produced by the turn-off current in the time domain, the author put forward with the calculation of the second field in the time domain with the turn-off effect, then through the all zone search algorithm to draw the all time apparent resistivity, so as to realize the turn-off current correction. Through calculation shows that for the multi-strata, the middle strata will be influenced by the close strata, but the curve that can reflect the basic underground electrical structures .
The transient electromagnetic method is one of the commonly used electromagnetic method in the geophysical exploration. In this paper,the author focus on the forward calculation of the transient electromagnetic method with electric dipoles which is less discussed nowadays. First, let the field theory deduces the homogeneous half-space and isotropic horizontal layered earth's vertical magnetic field, through the fast hankel transformation to realize frequency domain forward calculation, then through the G-S transformation to realize from the frequency domain to the time domain conversion. Through the iterative algorithm to obtained the apparent resistivity in the frequency domain. Since the turn-off effect produced by the turn-off current in the time domain, the author put forward with the calculation of the second field in the time domain with the turn-off effect, then through the all zone search algorithm to draw the all time apparent resistivity, so as to realize the turn-off current correction. Through calculation shows that for the multi-strata, the middle strata will be influenced by the close strata, but the curve that can reflect the basic underground electrical structures .
引文
[1] Fitterman D V,Anderson W L. Effect of transmitter turn-off time on transient s ounding[J].Geoexploration,1987,24 ,131-146
[2] Raiche A P. The effect of ramp function turn-off on the TEM response of layered earth exploration[J].Geophysics,1984,vol,15:37-41.
[3] Ward S H,Hohmann G W. Electromagnetic theory for geophysical application[A]. In:Nabighian M N,Ed. Electromagnetic methods in applied geophysics.SEG V 0l,theory
[4]蒋邦远.实用近区磁原瞬变电磁法勘探[M].北京:地质出版社,1998
[5]牛之琏.时间域电磁法原理[M].长沙:中南工业大学出版社,1992
[6]白登海,Meju M A.瞬变电磁法中两种关断电流对响应函数的影响及其应对策略[J].地震地质,2001,23(2):245-251
[7]嵇艳鞠,林君,等.ATTEM系统中电流关断期间瞬变电磁场响应求解的研究[J].地球物理学报, 2006, 49(6):1884-1890
[8]严良俊,胡文宝,陈清礼,等.长偏移距瞬变电磁测深法在碳酸盐岩覆盖区探测局部构造的应用效果[J].地震地质,2001,23(2):271-276
[9]傅君眉,冯恩信编著.高等电磁理论[M].西安:西安交通人学出版社,2000
[10] Kaufman A A and Keller G V. Inductive mining prospecting part: theory. Elsevier, 1985,11-138
[11]Nabighian,M N. Quasi-Static transient response of a conducting half-space-An approximate representation[J].Geophysics,1979,Vol,44 No.10,1700-1705
[12] Nabighian M N edal. Electromagnetic methods in applied Geophysics-Theory Volume I.Socicty of Exploration Geophysicsts,1988,313-503
[13] Aderson W L. Nonlinear Least-squares inversion of transient sounding for a central induction loop system[J].U.S.G.S Open-File Report,82-240
[14]Ravenhurst W R. Microcomputer modeling of fixed-loop time-domain EM systems. Canada Crone Geophysics Limited Technical Note,1987
[15] McNeill J D.EM37 Ground transient electromagnetic system: Calculated depth of exploration[J]. Geonics Limited Technical NoteTN-10,1980
[16] Eaton P A, Hohmann G W.A rapid inversion technique for transient electro -magnetic sounding[J].Physics of the Earth and Planetary Interiors,1989,53
[17]何继善.电法勘探的发展与展望[J].地球物理学报,1997,40(增刊):308-316
[18]朴化荣.瞬变电磁法现状及展望[M].见:罗延钟,史保连,朴化荣土编.勘查地球物理勘查地球化学文集第20集.北京:地质出版社,1998
[19]李实.高性能瞬变电磁仪的研制及人工神经网络专家系统在瞬变电磁法反演中的应用:[博士论文].西安:西安交通大学,2000
[20]李实,李创社.高性能瞬变电磁仪的研制及应用[J].物探与化探,2000 , 24 ( 1 ) : 76-80
[21]杨文采著.地球物理反演的理论与方法[M].北京:地质出版社,1997
[22]石显新,闫述,陈明生.瞬变电磁勘探中的低阻层屏蔽问题[J].煤炭学报,2005,30(2):160-163
[23]刘光鼎.中国海洋地球物理进展.地球物理学报[J].1997,40(增刊):46-49
[24]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
[25]白登海,Maxwell.A.Meju等.时间域瞬变电磁法中心方式全程视电阻率的数值计算[J].地球物理学报,2003,vol 46,No.5:697-704
[26]昌彦君,张桂青.电磁场从频率域转换到时间域的几种算法比较[J].物探化探计算技术,第17卷第3期,1995.8
[27]陈明生.电偶源瞬变电磁测深研究(一)—基本原理[J].煤田地质与勘探,1999,27(1):55-59
[28]陈明生.电偶源瞬变电磁测深研究(二)—瞬变电磁场的求解方法[J].煤田地质与勘探,1999,27(2):54-57
[29]陈明生.电偶源瞬变电磁测深研究(三)—人地表面瞬变电磁场[J].煤田地质与勘探,1999,27(3):58-61
[30]陈明生.电偶源瞬变电磁测深研究(四)—瞬变电磁测深视电阻率[J].煤田地质与勘探,1999,27(4):52-54
[31]陈明生.电偶源瞬变电磁测深研究(五)—实测感应电压转换成垂直磁场[J].煤田地质与勘探,1999,27(5):63-64
[32]严良俊,胡文宝.瞬变电磁测深一维反演及结果分析[J].江汉石油学院学报第16卷增刊,1994,12
[33]傅良魁主编.电法勘探教程[M].北京:地质出版社,1983
[34]朴化荣,殷长春.利用G-S逆拉氏变换法计算瞬变测深正演问题[J].物化探计算技术,1987,第9卷,第4期
[35]朴化荣.电磁测深法原理[M].北京:地质出版社,1991
[36]李金铭,罗延钟.电法勘探新进展[M].北京:地质出版社,1995
[37]殷长春,朴化荣.电磁测深法视电阻率定义问题的研究[J].物探与化探,第15卷,第4期,1991
[38]李貅.瞬变电磁测深的理论与应用[M].西安:陕西科学技术出版社,2002.9
[39]黄力军.电偶源瞬变电磁测深一维全区视电阻率解释方法研究[J].物探与化探第19卷第5期,1995年10月
[40]杨云见,王绪本,何展翔.瞬变电磁法中斜阶跃效应及常规的校正方法分析[J].物探与化探, 2006,28(2):129-132
[41] Hoversten G W,Morrison H F.Transient fields of a current loop sourse above a layered earth[J].Geophysics,1982,47(7):1068-1077
[42] Kaumfan A A. Frequeney and Transient Responses of Eleetromagnetic Fields Created by Currents in Confined Conductors[J].GeoPhysics,1978,43:1002-1010
[43] Beder C M and Orszag S A.Advanced mathematical methods for engineers and scientists[J].NewYork:MeGraw-Hill.Inc,1978
[44] Oristaglio M L.Diffusion of electromagnetic fields into the earth from a Iine source of current[J].Geophysies,1982,47(11):1585-1592
[45] Jopie,I.Adhidjaja,Gerald.W.Hohmann,and Michael.L.oristaglio.,Two dimen -sional transient Electromagnetic responses[J].Geophysics,vol 50,No.12 2849-2861
[46] Carsten Scholl,Stefan L,Helwig, Bulent Tezkan, Mark Goldman and UriKafri.1-D multimodel joint inversion of TEM-data over multidimensional structures[J]. Geophysies, Int. (2009) 176, 81–94
[47] Levy G M.Correction of measured transient electromagnetic filed over a layered half-spece[J].Geophysical Prospeeting,1969,vol 17,82-101
[48] Guimin liu.Effect of transmitter current waveform on airborne TEM response[J]. Exploration Geophysics ,1998,Vol,29:35-41
[49] Smith R S and Whitaker S A.Line Current filtering of fixed-loop transient electromagnetic date[J].Geophysical Prospeeting,1993,41
[50]Lee T.The effect of displacement current on time domain electromagnetic fields[J].Geophysics,Bull A,S. E. G, No. 3,1981,34-36
[2] Raiche A P. The effect of ramp function turn-off on the TEM response of layered earth exploration[J].Geophysics,1984,vol,15:37-41.
[3] Ward S H,Hohmann G W. Electromagnetic theory for geophysical application[A]. In:Nabighian M N,Ed. Electromagnetic methods in applied geophysics.SEG V 0l,theory
[4]蒋邦远.实用近区磁原瞬变电磁法勘探[M].北京:地质出版社,1998
[5]牛之琏.时间域电磁法原理[M].长沙:中南工业大学出版社,1992
[6]白登海,Meju M A.瞬变电磁法中两种关断电流对响应函数的影响及其应对策略[J].地震地质,2001,23(2):245-251
[7]嵇艳鞠,林君,等.ATTEM系统中电流关断期间瞬变电磁场响应求解的研究[J].地球物理学报, 2006, 49(6):1884-1890
[8]严良俊,胡文宝,陈清礼,等.长偏移距瞬变电磁测深法在碳酸盐岩覆盖区探测局部构造的应用效果[J].地震地质,2001,23(2):271-276
[9]傅君眉,冯恩信编著.高等电磁理论[M].西安:西安交通人学出版社,2000
[10] Kaufman A A and Keller G V. Inductive mining prospecting part: theory. Elsevier, 1985,11-138
[11]Nabighian,M N. Quasi-Static transient response of a conducting half-space-An approximate representation[J].Geophysics,1979,Vol,44 No.10,1700-1705
[12] Nabighian M N edal. Electromagnetic methods in applied Geophysics-Theory Volume I.Socicty of Exploration Geophysicsts,1988,313-503
[13] Aderson W L. Nonlinear Least-squares inversion of transient sounding for a central induction loop system[J].U.S.G.S Open-File Report,82-240
[14]Ravenhurst W R. Microcomputer modeling of fixed-loop time-domain EM systems. Canada Crone Geophysics Limited Technical Note,1987
[15] McNeill J D.EM37 Ground transient electromagnetic system: Calculated depth of exploration[J]. Geonics Limited Technical NoteTN-10,1980
[16] Eaton P A, Hohmann G W.A rapid inversion technique for transient electro -magnetic sounding[J].Physics of the Earth and Planetary Interiors,1989,53
[17]何继善.电法勘探的发展与展望[J].地球物理学报,1997,40(增刊):308-316
[18]朴化荣.瞬变电磁法现状及展望[M].见:罗延钟,史保连,朴化荣土编.勘查地球物理勘查地球化学文集第20集.北京:地质出版社,1998
[19]李实.高性能瞬变电磁仪的研制及人工神经网络专家系统在瞬变电磁法反演中的应用:[博士论文].西安:西安交通大学,2000
[20]李实,李创社.高性能瞬变电磁仪的研制及应用[J].物探与化探,2000 , 24 ( 1 ) : 76-80
[21]杨文采著.地球物理反演的理论与方法[M].北京:地质出版社,1997
[22]石显新,闫述,陈明生.瞬变电磁勘探中的低阻层屏蔽问题[J].煤炭学报,2005,30(2):160-163
[23]刘光鼎.中国海洋地球物理进展.地球物理学报[J].1997,40(增刊):46-49
[24]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
[25]白登海,Maxwell.A.Meju等.时间域瞬变电磁法中心方式全程视电阻率的数值计算[J].地球物理学报,2003,vol 46,No.5:697-704
[26]昌彦君,张桂青.电磁场从频率域转换到时间域的几种算法比较[J].物探化探计算技术,第17卷第3期,1995.8
[27]陈明生.电偶源瞬变电磁测深研究(一)—基本原理[J].煤田地质与勘探,1999,27(1):55-59
[28]陈明生.电偶源瞬变电磁测深研究(二)—瞬变电磁场的求解方法[J].煤田地质与勘探,1999,27(2):54-57
[29]陈明生.电偶源瞬变电磁测深研究(三)—人地表面瞬变电磁场[J].煤田地质与勘探,1999,27(3):58-61
[30]陈明生.电偶源瞬变电磁测深研究(四)—瞬变电磁测深视电阻率[J].煤田地质与勘探,1999,27(4):52-54
[31]陈明生.电偶源瞬变电磁测深研究(五)—实测感应电压转换成垂直磁场[J].煤田地质与勘探,1999,27(5):63-64
[32]严良俊,胡文宝.瞬变电磁测深一维反演及结果分析[J].江汉石油学院学报第16卷增刊,1994,12
[33]傅良魁主编.电法勘探教程[M].北京:地质出版社,1983
[34]朴化荣,殷长春.利用G-S逆拉氏变换法计算瞬变测深正演问题[J].物化探计算技术,1987,第9卷,第4期
[35]朴化荣.电磁测深法原理[M].北京:地质出版社,1991
[36]李金铭,罗延钟.电法勘探新进展[M].北京:地质出版社,1995
[37]殷长春,朴化荣.电磁测深法视电阻率定义问题的研究[J].物探与化探,第15卷,第4期,1991
[38]李貅.瞬变电磁测深的理论与应用[M].西安:陕西科学技术出版社,2002.9
[39]黄力军.电偶源瞬变电磁测深一维全区视电阻率解释方法研究[J].物探与化探第19卷第5期,1995年10月
[40]杨云见,王绪本,何展翔.瞬变电磁法中斜阶跃效应及常规的校正方法分析[J].物探与化探, 2006,28(2):129-132
[41] Hoversten G W,Morrison H F.Transient fields of a current loop sourse above a layered earth[J].Geophysics,1982,47(7):1068-1077
[42] Kaumfan A A. Frequeney and Transient Responses of Eleetromagnetic Fields Created by Currents in Confined Conductors[J].GeoPhysics,1978,43:1002-1010
[43] Beder C M and Orszag S A.Advanced mathematical methods for engineers and scientists[J].NewYork:MeGraw-Hill.Inc,1978
[44] Oristaglio M L.Diffusion of electromagnetic fields into the earth from a Iine source of current[J].Geophysies,1982,47(11):1585-1592
[45] Jopie,I.Adhidjaja,Gerald.W.Hohmann,and Michael.L.oristaglio.,Two dimen -sional transient Electromagnetic responses[J].Geophysics,vol 50,No.12 2849-2861
[46] Carsten Scholl,Stefan L,Helwig, Bulent Tezkan, Mark Goldman and UriKafri.1-D multimodel joint inversion of TEM-data over multidimensional structures[J]. Geophysies, Int. (2009) 176, 81–94
[47] Levy G M.Correction of measured transient electromagnetic filed over a layered half-spece[J].Geophysical Prospeeting,1969,vol 17,82-101
[48] Guimin liu.Effect of transmitter current waveform on airborne TEM response[J]. Exploration Geophysics ,1998,Vol,29:35-41
[49] Smith R S and Whitaker S A.Line Current filtering of fixed-loop transient electromagnetic date[J].Geophysical Prospeeting,1993,41
[50]Lee T.The effect of displacement current on time domain electromagnetic fields[J].Geophysics,Bull A,S. E. G, No. 3,1981,34-36