磁异常总梯度模量反演
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摘要
磁异常解释通常依赖于准确的磁化方向,若磁化方向未知或者不准确,解释的结果就会受到影响.磁异常总梯度模量具有不受或弱受磁化方向影响的特点,因此本文实现磁异常总梯度模量的最优化反演,用于解决磁化方向未知或者不准确情况下的反演问题.通过分析二度体的总梯度模量公式,指出二维总梯度模量的曲线形态与磁化方向参数无关,但幅值与磁化方向参数有关,因此对反演中二维总梯度模正演值采用了一种归一—还原的方法,使得正演总梯度模量能够保幅,且与磁化方向参数完全无关;以直立长方体模型计算结果说明三维总梯度模受磁化方向的影响比总磁场异常小.通过二度板状体和直立长方体模型的反演试验,说明了利用总梯度模数据反演的结果不受或少受磁化方向的影响,可用于磁化方向未知或不准确情况下的反演.该方法在江苏某铁矿实例中取得了良好的地质效果.
Interpretation of magnetic anomaly is usually dependent on accurate magnetization direction.If the magnetization direction is unknown or inaccurate,the results of interpretation will be affected.Total gradient modulus of magnetic anomaly is independent of or minimally dependent on magnetization direction,so this article achieves the optimization inversion of magnetic gradient modulus to solve the inversion when the magnetization direction is unknown or inaccurate.Through analyzing the total gradient modulus formula of 2Dbody,we point out that the curve shape of the gradient modulus has nothing to do with the direction of magnetization parameters,but the magnitude of that does not.A method called normalization-reduction is applied on predictive total gradient modulus in inversion,which makes the predictive total gradient modulus changeless of magnitude and then independent of magnetization direction;Forward results of Vertical cube show that affection from magnetization direction for 3Dtotal gradient modulus is less than that for total magnetic anomalies.Inversion tests of 2Dtabular body and vertical cube indicate that the inversion results using total gradient modulus data are not affected or less affected by the magnetization direction,which can be used for inversion when the magnetization direction is unknown or inaccurate.This method shows good geological results on the application of an iron deposit of Jiangsu.
Interpretation of magnetic anomaly is usually dependent on accurate magnetization direction.If the magnetization direction is unknown or inaccurate,the results of interpretation will be affected.Total gradient modulus of magnetic anomaly is independent of or minimally dependent on magnetization direction,so this article achieves the optimization inversion of magnetic gradient modulus to solve the inversion when the magnetization direction is unknown or inaccurate.Through analyzing the total gradient modulus formula of 2Dbody,we point out that the curve shape of the gradient modulus has nothing to do with the direction of magnetization parameters,but the magnitude of that does not.A method called normalization-reduction is applied on predictive total gradient modulus in inversion,which makes the predictive total gradient modulus changeless of magnitude and then independent of magnetization direction;Forward results of Vertical cube show that affection from magnetization direction for 3Dtotal gradient modulus is less than that for total magnetic anomalies.Inversion tests of 2Dtabular body and vertical cube indicate that the inversion results using total gradient modulus data are not affected or less affected by the magnetization direction,which can be used for inversion when the magnetization direction is unknown or inaccurate.This method shows good geological results on the application of an iron deposit of Jiangsu.
引文
[1]Nabighian M N.The analytic signal of two-dimensional magnetic bodies with polygonal cross-section:its properties and use for automated anomaly interpretation[J].Geophysics,1972,37(3):507-517.
[2]Nabighian M N.Toward a three-dimensional automatic interpretation of potential field data via generalized Hilbert transforms:Fundamental relations[J].Geophysics,1984,49(6):780-786.
[3]Agarwal B N P,Shaw R K.Comment on'An analytic signal approach to the interpretation of total field magnetic anomaliesby Shuang Qin[J].Geophysical Prospecting,1996,44(5):911-914.
[4]Paine J,Haederle M,Flis M.Using transformed TMI data to invert for remanently magnetised bodies[J].Exploration Geophysics,2001,32(4):238-242.
[5]Li X.Understanding 3Danalytic signal amplitude[J].Geophysics,2006,71(2):L13-L16.
[6]Roest W R,Verhoef J,Pilkington M.Magnetic interpretation using the 3-D analytic signal[J].Geophysics,1992,57(1):116-125.
[7]Qin S.An analytic signal approach to the interpretation of total field magnetic anomalies[J].Geophysical Prospecting,1994,42(6):655-675.
[8]胡中栋,余钦范,楼海.三维解析信号法[J].物探化探计算技术,1995,17(3):36-42.Hu Z D,Yu Q F,Lou H.3-D analytic signal method[J].Computing Techniques for Geophysical and Geochemical Exploration(in Chinese),1995,17(3):36-42.
[9]黄临平,管志宁.利用磁异常总梯度模确定磁源边界位置[J].华东地质学院学报,1998,21(2):143-150.Huang L P,Guan Z N.The determination of magnetic causative boundaries using total gradient modules of magnetic anomalies[J].Journal of East China Geological Institute(in Chinese),1998,21(2):143-150.
[10]郭志宏,熊盛青,曹建平.航磁异常总梯度模反演方法的实用化改进及软件研制[J].物探与化探,2004,28(6):518-522.Guo Z H,Xiong S Q,Cao J P.The practical improvement and software development of total gradient amplitude inversion of aeromagnetic plane grid data[J].Geophysical and Geochemical Exploration(in Chinese),2004,28(6):518-522.
[11]Hsu S K,Sibuet J C,Shyu C T.High-resolution detection of geologic boundaries from potential-field anomalies:An enhanced analytic signal technique[J].Geophysics,1996,61(2):373-386.
[12]Debeglia N,Corpel J.Automatic 3-D interpretation of potential field data using analytic signal derivatives[J].Geophysics,1997,62(1):87-96.
[13]王万银,邱之云,杨永,等.位场边缘识别方法研究进展[J].地球物理学进展,2010,25(1):196-210.Wang W Y,Qiu Z Y,Yang Y,et al.Some advances in the edge recognition of the potential field[J].Progress in Geophysics(in Chinese),2010,25(1):196-210.
[14]王万银.位场总水平导数极值位置空间变化规律研究[J].地球物理学报,2010,53(9):2257-2270.Wang W Y.Spatial variation law of the extreme value positions of total horizontal derivative for potential field data[J].Chinese J.Geophys.(in Chinese),2010,53(9):2257-2270.
[15]王万银.位场解析信号振幅极值位置空间变化规律研究[J].地球物理学报,2012,55(4):1288-1299.Wang W Y.Spatial variation law of the extreme value position of analytical signal amplitude for potential field data[J].Chinese J.Geophys.(in Chinese),2012,55(4):1288-1299.
[16]骆遥,王明,罗锋,等.重磁场二维希尔伯特变换——直接解析信号解释方法[J].地球物理学报,2011,54(7):1912-1920.Luo Y,Wang M,Luo F,et al.Direct analytic signal interpretation of potential field data using 2-D Hilbert transform[J].Chinese J.Geophys.(in Chinese),2011,54(7):1912-1920.
[17]管志宁,姚长利.倾斜板体磁异常总梯度模反演方法[J].地球科学-中国地质大学学报,1997,22(1):81-85.Guan Z N,Yao C L.Inversion of the total gradient modulus of magnetic anomaly due to dipping dike[J].Earth Science:Journal of China University of Geosciences(in Chinese),1997,22(1):81-85.
[18]Salem A,Ravat D.A combined analytic signal and Euler method(AN-EUL)for automatic interpretation of magnetic data[J].Geophysics,2003,68(6):1952-1961.
[19]张季生,高锐,李秋生,等.欧拉反褶积与解析信号相结合的位场反演方法[J].地球物理学报,2011,54(6):1634-1641.Zhang J S,Gao R,Li Q S,et al.A combined Euler and analytic signal method for an inversion calculation of potential data[J].Chinese J.Geophys.(in Chinese),2011,54(6):1634-1641.
[20]Shearer S E,Li Y G.3Dinversion of magnetic total gradient in the presence of remanent magnetization:74th Annual Inter-national Meeting[C].SEG,Technical Program Expanded Abstracts,2004,23:774-777.
[21]Shearer S E.3-D inversion of magnetic data in the presence of remanent magnetization[D].Colorado:Department of Geophysics Colorado School of Mines Golden,2005.
[22]Krahenbuhl R A,Li Y G.Influence of self-demagnetization effect on data interpretation in strongly magnetic environments[C].SEG Expanded Abstracts,2007,26:713-717.
[23]管志宁.地磁场与磁力勘探[M].北京:地质出版社,2005:109-110,119-121.Guan Z N.Geomagnetic Field and Magnetic Exploration[M].Beijing:Geological Publishing House(in Chinese),2005:109-110,119-121.
[24]姚姚.地球物理反演基本理论与应用方法[M].武汉:中国地质大学出版社,2002:90-93.Yao Y.Basic Theory and Application of Geophysical Inversion[M].Wuhan:China University of Geosciences Press(in Chinese),2002:90-93.
[2]Nabighian M N.Toward a three-dimensional automatic interpretation of potential field data via generalized Hilbert transforms:Fundamental relations[J].Geophysics,1984,49(6):780-786.
[3]Agarwal B N P,Shaw R K.Comment on'An analytic signal approach to the interpretation of total field magnetic anomaliesby Shuang Qin[J].Geophysical Prospecting,1996,44(5):911-914.
[4]Paine J,Haederle M,Flis M.Using transformed TMI data to invert for remanently magnetised bodies[J].Exploration Geophysics,2001,32(4):238-242.
[5]Li X.Understanding 3Danalytic signal amplitude[J].Geophysics,2006,71(2):L13-L16.
[6]Roest W R,Verhoef J,Pilkington M.Magnetic interpretation using the 3-D analytic signal[J].Geophysics,1992,57(1):116-125.
[7]Qin S.An analytic signal approach to the interpretation of total field magnetic anomalies[J].Geophysical Prospecting,1994,42(6):655-675.
[8]胡中栋,余钦范,楼海.三维解析信号法[J].物探化探计算技术,1995,17(3):36-42.Hu Z D,Yu Q F,Lou H.3-D analytic signal method[J].Computing Techniques for Geophysical and Geochemical Exploration(in Chinese),1995,17(3):36-42.
[9]黄临平,管志宁.利用磁异常总梯度模确定磁源边界位置[J].华东地质学院学报,1998,21(2):143-150.Huang L P,Guan Z N.The determination of magnetic causative boundaries using total gradient modules of magnetic anomalies[J].Journal of East China Geological Institute(in Chinese),1998,21(2):143-150.
[10]郭志宏,熊盛青,曹建平.航磁异常总梯度模反演方法的实用化改进及软件研制[J].物探与化探,2004,28(6):518-522.Guo Z H,Xiong S Q,Cao J P.The practical improvement and software development of total gradient amplitude inversion of aeromagnetic plane grid data[J].Geophysical and Geochemical Exploration(in Chinese),2004,28(6):518-522.
[11]Hsu S K,Sibuet J C,Shyu C T.High-resolution detection of geologic boundaries from potential-field anomalies:An enhanced analytic signal technique[J].Geophysics,1996,61(2):373-386.
[12]Debeglia N,Corpel J.Automatic 3-D interpretation of potential field data using analytic signal derivatives[J].Geophysics,1997,62(1):87-96.
[13]王万银,邱之云,杨永,等.位场边缘识别方法研究进展[J].地球物理学进展,2010,25(1):196-210.Wang W Y,Qiu Z Y,Yang Y,et al.Some advances in the edge recognition of the potential field[J].Progress in Geophysics(in Chinese),2010,25(1):196-210.
[14]王万银.位场总水平导数极值位置空间变化规律研究[J].地球物理学报,2010,53(9):2257-2270.Wang W Y.Spatial variation law of the extreme value positions of total horizontal derivative for potential field data[J].Chinese J.Geophys.(in Chinese),2010,53(9):2257-2270.
[15]王万银.位场解析信号振幅极值位置空间变化规律研究[J].地球物理学报,2012,55(4):1288-1299.Wang W Y.Spatial variation law of the extreme value position of analytical signal amplitude for potential field data[J].Chinese J.Geophys.(in Chinese),2012,55(4):1288-1299.
[16]骆遥,王明,罗锋,等.重磁场二维希尔伯特变换——直接解析信号解释方法[J].地球物理学报,2011,54(7):1912-1920.Luo Y,Wang M,Luo F,et al.Direct analytic signal interpretation of potential field data using 2-D Hilbert transform[J].Chinese J.Geophys.(in Chinese),2011,54(7):1912-1920.
[17]管志宁,姚长利.倾斜板体磁异常总梯度模反演方法[J].地球科学-中国地质大学学报,1997,22(1):81-85.Guan Z N,Yao C L.Inversion of the total gradient modulus of magnetic anomaly due to dipping dike[J].Earth Science:Journal of China University of Geosciences(in Chinese),1997,22(1):81-85.
[18]Salem A,Ravat D.A combined analytic signal and Euler method(AN-EUL)for automatic interpretation of magnetic data[J].Geophysics,2003,68(6):1952-1961.
[19]张季生,高锐,李秋生,等.欧拉反褶积与解析信号相结合的位场反演方法[J].地球物理学报,2011,54(6):1634-1641.Zhang J S,Gao R,Li Q S,et al.A combined Euler and analytic signal method for an inversion calculation of potential data[J].Chinese J.Geophys.(in Chinese),2011,54(6):1634-1641.
[20]Shearer S E,Li Y G.3Dinversion of magnetic total gradient in the presence of remanent magnetization:74th Annual Inter-national Meeting[C].SEG,Technical Program Expanded Abstracts,2004,23:774-777.
[21]Shearer S E.3-D inversion of magnetic data in the presence of remanent magnetization[D].Colorado:Department of Geophysics Colorado School of Mines Golden,2005.
[22]Krahenbuhl R A,Li Y G.Influence of self-demagnetization effect on data interpretation in strongly magnetic environments[C].SEG Expanded Abstracts,2007,26:713-717.
[23]管志宁.地磁场与磁力勘探[M].北京:地质出版社,2005:109-110,119-121.Guan Z N.Geomagnetic Field and Magnetic Exploration[M].Beijing:Geological Publishing House(in Chinese),2005:109-110,119-121.
[24]姚姚.地球物理反演基本理论与应用方法[M].武汉:中国地质大学出版社,2002:90-93.Yao Y.Basic Theory and Application of Geophysical Inversion[M].Wuhan:China University of Geosciences Press(in Chinese),2002:90-93.