磁电勘探法二维数值模拟研究
|
摘要
磁电勘探法是属于测磁场的传导类电法勘探,是在一般电法中将测量地面上两点间电位差,改成逐点观测磁场的一类勘探方法。这种磁场(总磁场和一次磁场以及二次极化电流引起的二次磁场)的异常值,均是由地中传导电流引起的,它们主要决定于地质目标的导电性作用及电化学作用。磁电勘探法主要包括磁电阻率法和磁激发极化法。磁电阻率法是在供电期间观测总磁场或一次磁场的分布规律,以此研究地质目标的导电性能和导磁性能,实现找矿或者解决其他地质问题的一种勘探方法。与磁电阻率法不同,磁激发极化法是在断电后测量二次极化电流引起的二次磁场,以此研究地质目标的电化学性能。
论文采用有限单元法实现了磁电勘探法二维数值模拟,并在数值模拟的基础上进行了相应的研究和探讨。通过对一些常见二维模型的数值模拟,可以发现,一方面可以根据磁电勘探法来判断异常体与围岩的电阻率关系;另一方面还可以判断异常体的走向和形状。除此,还对磁电勘探法克服屏蔽层的能力和区分组合异常体的能力进行了评价。
然而,需要强调的是,磁电阻率法和磁激发极化法只能按照磁场的相对变化来发现地质目标或解决其他地质问题,其有效的应用对象是调查水平方向上的电化学作用和电阻率的不均匀情况。
Magnetometric is a prospecting method of measuring the magnetic field, and it is a magnetometric conducting method. Normal electrical prospecting is a method of measuring potential diference between two surface points, but magnetometric is a prospecting method of measuring magnetic field. The anomaly of magnetic field (total field ,primary field or the secondary magnetic field ) is caused by the conducting current , and they are mainly based on the conductivity and electrochemical action of the geological target body. Magnetometric includes magnetometric resistivity(MMR) method and magnetic induced polarization(MIP) method. Magnetomtric resistivity is a method of measuring total magnetic field or primary magnetic field in order to investigate the electrical conductivity and magnetic conductivity,so as to achieve the purpose of find orebody or solve other geological purposes. Differing from magnetometric resistivity ,magnetometric induced polarization method is a method of measuring the secondary magnetic field caused by secondary current to investigate the electrochemical action of the geological targets.
The thesis uses two-dimensional Finite Element Method,and realizes the aim of numerical simulations by computer. On the basis of research and study of forward simulations ,I have done some Exploring and Probing. Through the simunation of some common two-dimensional numerical models,we can draw some conclusions.On the one hand, we can judge the relationship of the resistivity between wall rock and orebody. On the other hand,we can know the attitude and trend of orebody.
However, need to be stressed is that the magnetometric can only find orebody and solve other geological problems base on the relative magnetic field change. Its effective application is to investigate the electrochemical action and the nonuniformity of resistivity on the horizontal direction.
论文采用有限单元法实现了磁电勘探法二维数值模拟,并在数值模拟的基础上进行了相应的研究和探讨。通过对一些常见二维模型的数值模拟,可以发现,一方面可以根据磁电勘探法来判断异常体与围岩的电阻率关系;另一方面还可以判断异常体的走向和形状。除此,还对磁电勘探法克服屏蔽层的能力和区分组合异常体的能力进行了评价。
然而,需要强调的是,磁电阻率法和磁激发极化法只能按照磁场的相对变化来发现地质目标或解决其他地质问题,其有效的应用对象是调查水平方向上的电化学作用和电阻率的不均匀情况。
Magnetometric is a prospecting method of measuring the magnetic field, and it is a magnetometric conducting method. Normal electrical prospecting is a method of measuring potential diference between two surface points, but magnetometric is a prospecting method of measuring magnetic field. The anomaly of magnetic field (total field ,primary field or the secondary magnetic field ) is caused by the conducting current , and they are mainly based on the conductivity and electrochemical action of the geological target body. Magnetometric includes magnetometric resistivity(MMR) method and magnetic induced polarization(MIP) method. Magnetomtric resistivity is a method of measuring total magnetic field or primary magnetic field in order to investigate the electrical conductivity and magnetic conductivity,so as to achieve the purpose of find orebody or solve other geological purposes. Differing from magnetometric resistivity ,magnetometric induced polarization method is a method of measuring the secondary magnetic field caused by secondary current to investigate the electrochemical action of the geological targets.
The thesis uses two-dimensional Finite Element Method,and realizes the aim of numerical simulations by computer. On the basis of research and study of forward simulations ,I have done some Exploring and Probing. Through the simunation of some common two-dimensional numerical models,we can draw some conclusions.On the one hand, we can judge the relationship of the resistivity between wall rock and orebody. On the other hand,we can know the attitude and trend of orebody.
However, need to be stressed is that the magnetometric can only find orebody and solve other geological problems base on the relative magnetic field change. Its effective application is to investigate the electrochemical action and the nonuniformity of resistivity on the horizontal direction.
引文
Chave,A.D., Constable,S.C., Edwards, R.N.Electrical exploration methods for the sea floor, in Nabighian,M.N.,Ed.Electromagnetic methods in applied geophysics,1990
Cheesman,S.J,Edwards R.N., Current channeling in square plates with application to the magnetometric resistivity method. Geophys. Prosp,1989,37:553～581
Edwards,R.N.,Law,L.K.,Delaurier,J.M.,On measuring the electrical conductivity of the oceanic crust by a modified magnetometric resistivity method. J.Geophys. 1981,86:11609～11615
Edwards,R.N.,Lee,H.,Nabighian,M.N.On the theory of magnetometric resistivity (MMR) methods. Geophysics,1978,43:1176～1203
Edwards,R.N.,The cross-hole magnetometric resisitivity(MMR)response of a disc conductor.Geophs.Prosp,1984,32:955～969
Howland-rose,A.W.,Linfrd,G.,Pitcher,D.H.,etal.Some recent magnetic induced polariziation development-part 2:Survey results.Geophysics,1980b,45:55~75
Misac N.Nabighian.Electromagnetic methds in applied geophysics.Society of Exploration Geophysicists ,1991 .
Seigel,H.O.,Howland-Rose,A.W.,magnetic induced-polariziaton method ,Society of Exploration Geophysicists,1990
安晓卫,邵伟平.二维问题的有限元网格的自动剖分.沈阳工业学院学报,13(4),1994
崔焕敏等.磁电阻率法和磁激法极化法,世界核地质科学,1983, No.4
邓靖武.磁电法正演理论研究,北京:中国地质大学](北京),2005
傅良魁.磁电勘探法原理,北京:地质出版社,1984
傅良魁.论被动源磁电勘探理论,北京:地球物理学报,1982,No.6
傅良魁.应用地球物理教程---电法、放射性、地热,北京:地质出版社,1991
江乐玉,雷宛.地球物理数据处理教程,北京:地质出版社,2006
李金铭,罗延钟.电法勘探新进展,北京:地质出版社,1996
李金铭等.地电场与电法勘探,北京:地质出版社,2001
刘尔烈等.有限单元法及程序设计,天津:天津大学出版社,1999
罗延钟,张桂青.电子计算机在电法勘探中的应用,武汉:武汉地质学院出版,1987
彭国伦.Fortran 95程序设计,北京:中国电力出版社,2002
王飞,杨贤.大地磁电阻率法—一种新的地球物理方法,北京:铀矿地质
王家映.地球物理反演理论,北京:高等教育出版社,2003
王勖成.有限单元法,北京:清华大学出版社,2003
徐世浙.地球物理中的有限单元法,北京:科学出版社,1994
杨建文.起伏地形点电源地下传导电流磁场表示——磁电阻率法地形改正,桂林冶金地质学院院报,1991
杨进.应用地球物理数值模拟的迭代有限元法,北京:地质出版社,1996
张书成.磁电阻率法的地质效果,北京:地质勘探,1987,No.6
郑阿奇等.Matlab实用教程,北京:电子工业出版社,2002
Cheesman,S.J,Edwards R.N., Current channeling in square plates with application to the magnetometric resistivity method. Geophys. Prosp,1989,37:553～581
Edwards,R.N.,Law,L.K.,Delaurier,J.M.,On measuring the electrical conductivity of the oceanic crust by a modified magnetometric resistivity method. J.Geophys. 1981,86:11609～11615
Edwards,R.N.,Lee,H.,Nabighian,M.N.On the theory of magnetometric resistivity (MMR) methods. Geophysics,1978,43:1176～1203
Edwards,R.N.,The cross-hole magnetometric resisitivity(MMR)response of a disc conductor.Geophs.Prosp,1984,32:955～969
Howland-rose,A.W.,Linfrd,G.,Pitcher,D.H.,etal.Some recent magnetic induced polariziation development-part 2:Survey results.Geophysics,1980b,45:55~75
Misac N.Nabighian.Electromagnetic methds in applied geophysics.Society of Exploration Geophysicists ,1991 .
Seigel,H.O.,Howland-Rose,A.W.,magnetic induced-polariziaton method ,Society of Exploration Geophysicists,1990
安晓卫,邵伟平.二维问题的有限元网格的自动剖分.沈阳工业学院学报,13(4),1994
崔焕敏等.磁电阻率法和磁激法极化法,世界核地质科学,1983, No.4
邓靖武.磁电法正演理论研究,北京:中国地质大学](北京),2005
傅良魁.磁电勘探法原理,北京:地质出版社,1984
傅良魁.论被动源磁电勘探理论,北京:地球物理学报,1982,No.6
傅良魁.应用地球物理教程---电法、放射性、地热,北京:地质出版社,1991
江乐玉,雷宛.地球物理数据处理教程,北京:地质出版社,2006
李金铭,罗延钟.电法勘探新进展,北京:地质出版社,1996
李金铭等.地电场与电法勘探,北京:地质出版社,2001
刘尔烈等.有限单元法及程序设计,天津:天津大学出版社,1999
罗延钟,张桂青.电子计算机在电法勘探中的应用,武汉:武汉地质学院出版,1987
彭国伦.Fortran 95程序设计,北京:中国电力出版社,2002
王飞,杨贤.大地磁电阻率法—一种新的地球物理方法,北京:铀矿地质
王家映.地球物理反演理论,北京:高等教育出版社,2003
王勖成.有限单元法,北京:清华大学出版社,2003
徐世浙.地球物理中的有限单元法,北京:科学出版社,1994
杨建文.起伏地形点电源地下传导电流磁场表示——磁电阻率法地形改正,桂林冶金地质学院院报,1991
杨进.应用地球物理数值模拟的迭代有限元法,北京:地质出版社,1996
张书成.磁电阻率法的地质效果,北京:地质勘探,1987,No.6
郑阿奇等.Matlab实用教程,北京:电子工业出版社,2002