位场垂向梯度最佳自比值的边界检测技术
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摘要
位场梯度换算在地质体边界检测中有着重要的应用.但传统的梯度算法易受干扰影响,计算稳定性差,且很难在复杂的叠加异常中识别出小型地质体的边界.鉴于此,本文给出了自比值的定义,提出了能够处理高阶导数的位场垂向梯度最佳自比值的边界检测方法,阐述了方法的数学含义和物理意义.模型试验表明,垂向梯度最佳自比值算法不仅计算稳定性强,而且能清晰地检测出传统梯度算法无法检测的模型体边界.在地质条件复杂的鸭绿江盆地的重力异常实例应用中,垂向三阶导数最佳自比值计算结果识别出的构造边界与实际地质体分布有着较好的对应关系,这不但与前人的工作成果互为佐证,而且自比值圈定的负异常分布区能较好地反映出浑江煤田的工作范围.
Derivative calculation of potential-field is widely used in edge detection of geologic bodies.However,the traditional gradient methods are susceptible to noise disturbance,and lead to the unstability of the results.Besides,the edges of small-sized geologic bodies are difficult to be detected because of superimposed anomaly.In this paper,we give the definition of auto-ratio and present a new method for edge detection by using optimal auto-ratio of vertical derivative,and elaborate mathematical implication and physical meaning of this method.Model test shows that optimal auto-ratio of vertical gradient has the ability to strongly suppress noise disturbance and can accurately detect the edges of geologic bodies which cannot be recognized by traditional edge detection methods.In application,we choose gravity anomaly of Yalujiang basin whose geological conditions are very complex to test the optimal auto-ratio method.It is shown that the optimal auto-ratio of third-order vertical derivative recognizes tectonic boundaries which have good correspondence with distribution characteristics of geologic bodies.The result is a case in point verifying former research results,and the auto-ratio delineates negative gravity anomaly zones which can preferably reflect the work area of Hunjiang coalfield.
Derivative calculation of potential-field is widely used in edge detection of geologic bodies.However,the traditional gradient methods are susceptible to noise disturbance,and lead to the unstability of the results.Besides,the edges of small-sized geologic bodies are difficult to be detected because of superimposed anomaly.In this paper,we give the definition of auto-ratio and present a new method for edge detection by using optimal auto-ratio of vertical derivative,and elaborate mathematical implication and physical meaning of this method.Model test shows that optimal auto-ratio of vertical gradient has the ability to strongly suppress noise disturbance and can accurately detect the edges of geologic bodies which cannot be recognized by traditional edge detection methods.In application,we choose gravity anomaly of Yalujiang basin whose geological conditions are very complex to test the optimal auto-ratio method.It is shown that the optimal auto-ratio of third-order vertical derivative recognizes tectonic boundaries which have good correspondence with distribution characteristics of geologic bodies.The result is a case in point verifying former research results,and the auto-ratio delineates negative gravity anomaly zones which can preferably reflect the work area of Hunjiang coalfield.
引文
[1]王万银,邱之云,杨永等.位场边缘识别方法研究进展.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 theedge recognition of the potential field.Progress in Geophys.(in Chinese),2010,25(1):196-210.
[2]Evjen H M.The place of the vertical gradient in gravitationalinterpretations.Geophysics,1936,1(1):127-136.
[3]Cordell L.Gravimetric expression of graben faulting in SantaFe Country and the Espanola Basin.New Mexico:NewMexico Geol.Soc.Guidebook,30th Field Conf.,1979:59-64.
[4]Miller H G,Singh V.Potential tilt—A new concept forlocation of potential field sources.Journal of AppliedGeophysics,1994,32(2-3):213-217.
[5]Verduzco B,Fairhead J D,Green C M,et al.New insightsinto magnetic derivatives for structural mapping.TheLeading Edge,2004,23(2):116-119.
[6]Wijns C,Perez C,Kowalczyk P.Theta map:edge detectionin magnetic data.Geophysics,2005,70(4):39-43.
[7]Cooper G R J.Balancing images of potential-field data.Geophysics,2009,74(3):L17-L20.
[8]Thompson D T.EULDPH:A new technique for makingcomputer-assisted depth estimates from magnetic data.Geophysics,1982,47(1):31-37.
[9]Reid A B,Allsop J M,Granser H,et al.Magneticinterpretation in three dimensions using Euler deconvolution.Geophysics,1990,55(1):80-91.
[10]Hansen R O,Laura S.Multiple-source Euler deconvolution.Geophysics,2002,67(2):525-535.
[11]杨高印.位场数据处理的一项新技术——小子域滤波法.石油地球物理勘探,1995,30(2):240-244.Yang G Y.A new technique for potential-field dataprocessing:small subdomain filtering.Oil GeophysicalProspecting(in Chinese),1995,30(2):240-244.
[12]Cooper G R J,Cowan D R.Edge enhancement of potential-field data using normalized statistics.Geophysics,2008,73(3):1-4.
[13]王彦国,王祝文,张凤旭等.基于均方差比归一化垂向梯度法的位场边界检测.中国石油大学学报(自然科学版),2012,36(2):86-90.Wang Y G,Wang Z W,Zhang F X,et al.Edge detection ofpotential field based on normalized vertical gradient of meansquare error ratio.Journal of China University ofPetroleum(Edition of Natural Science),2012,36(2):86-90.
[14]张恒磊,刘天佑,杨宇山.各向异性标准化方差计算重磁源边界.地球物理学报,2011,54(7):1921-1927.Zhang H L,Liu T Y,Yang Y S.Calculation of gravity andmagnetic source boundary based on anisotropy normalizedvariance.Chinese J.Geophys.(in Chinese),2011,54(7):1921-1927.
[15]张凤旭,张凤琴,刘财等.断裂构造精细解释技术——三方向小子域滤波.地球物理学报,2007,50(5):1543-1550.Zhang F X,Zhang F Q,Liu C,et al.A technique forelaborate explanation of faulted structures:three-directionalsmall subdomain filtering.Chinese J.Geophys.(in Chinese),2007,50(5):1543-1550.
[16]张凤旭,张兴洲,张凤琴等.中国东北地区重力场研究——利用改进的三方向小子域滤波划分主构造线及大地构造单元.地球物理学报,2010,53(6):1475-1485.Zhang F X,Zhang X Z,Zhang F Q,et al.Study of gravityfield in Northeastern China area:Classification of mainstructure lines and tectonic units using the improved three-directional small subdomain filtering.Chinese J.Geophys.(in Chinese),2010,53(6):1475-1485.
[17]高光珠,李忠武,余理富等.归一化互相关系数在图像序列目标检测中的应用.计算机工程与科学,2005,27(3):38-40.Gao G Z,Li Z W,Yu L F,et al.Application of thenormalized cross correlation coefficient in image sequenceobject detection.Computer Engineering and Science(inChinese),2005,27(3):38-40.
[18]曾华霖,许德树.最佳向上延拓高度的估计.地学前缘,2002,9(2):499-504.Zeng H L,Xu D S.Estimation of optimum upwardcontinuation height.Earth Science Frontiers(in Chinese),2002,9(2):499-504.
[19]孟小红,刘国锋,陈召曦等.基于剩余异常相关成像的重磁物性反演方法.地球物理学报,2012,55(1):304-309.Meng X H,Liu G F,Chen Z X,et al.3-D gravity andmagnetic inversion for physical properties based on residualanomaly correlation.Chinese J.Geophys.(in Chinese),2012,55(1):304-309.
1)实际资料来源于中国石油天然气股份有限公司吉林分公司(吉林油田).
3)刘财,张凤旭.吉林省南部重磁资料处理与解释(成果报告).吉林大学,2011.
[2]Evjen H M.The place of the vertical gradient in gravitationalinterpretations.Geophysics,1936,1(1):127-136.
[3]Cordell L.Gravimetric expression of graben faulting in SantaFe Country and the Espanola Basin.New Mexico:NewMexico Geol.Soc.Guidebook,30th Field Conf.,1979:59-64.
[4]Miller H G,Singh V.Potential tilt—A new concept forlocation of potential field sources.Journal of AppliedGeophysics,1994,32(2-3):213-217.
[5]Verduzco B,Fairhead J D,Green C M,et al.New insightsinto magnetic derivatives for structural mapping.TheLeading Edge,2004,23(2):116-119.
[6]Wijns C,Perez C,Kowalczyk P.Theta map:edge detectionin magnetic data.Geophysics,2005,70(4):39-43.
[7]Cooper G R J.Balancing images of potential-field data.Geophysics,2009,74(3):L17-L20.
[8]Thompson D T.EULDPH:A new technique for makingcomputer-assisted depth estimates from magnetic data.Geophysics,1982,47(1):31-37.
[9]Reid A B,Allsop J M,Granser H,et al.Magneticinterpretation in three dimensions using Euler deconvolution.Geophysics,1990,55(1):80-91.
[10]Hansen R O,Laura S.Multiple-source Euler deconvolution.Geophysics,2002,67(2):525-535.
[11]杨高印.位场数据处理的一项新技术——小子域滤波法.石油地球物理勘探,1995,30(2):240-244.Yang G Y.A new technique for potential-field dataprocessing:small subdomain filtering.Oil GeophysicalProspecting(in Chinese),1995,30(2):240-244.
[12]Cooper G R J,Cowan D R.Edge enhancement of potential-field data using normalized statistics.Geophysics,2008,73(3):1-4.
[13]王彦国,王祝文,张凤旭等.基于均方差比归一化垂向梯度法的位场边界检测.中国石油大学学报(自然科学版),2012,36(2):86-90.Wang Y G,Wang Z W,Zhang F X,et al.Edge detection ofpotential field based on normalized vertical gradient of meansquare error ratio.Journal of China University ofPetroleum(Edition of Natural Science),2012,36(2):86-90.
[14]张恒磊,刘天佑,杨宇山.各向异性标准化方差计算重磁源边界.地球物理学报,2011,54(7):1921-1927.Zhang H L,Liu T Y,Yang Y S.Calculation of gravity andmagnetic source boundary based on anisotropy normalizedvariance.Chinese J.Geophys.(in Chinese),2011,54(7):1921-1927.
[15]张凤旭,张凤琴,刘财等.断裂构造精细解释技术——三方向小子域滤波.地球物理学报,2007,50(5):1543-1550.Zhang F X,Zhang F Q,Liu C,et al.A technique forelaborate explanation of faulted structures:three-directionalsmall subdomain filtering.Chinese J.Geophys.(in Chinese),2007,50(5):1543-1550.
[16]张凤旭,张兴洲,张凤琴等.中国东北地区重力场研究——利用改进的三方向小子域滤波划分主构造线及大地构造单元.地球物理学报,2010,53(6):1475-1485.Zhang F X,Zhang X Z,Zhang F Q,et al.Study of gravityfield in Northeastern China area:Classification of mainstructure lines and tectonic units using the improved three-directional small subdomain filtering.Chinese J.Geophys.(in Chinese),2010,53(6):1475-1485.
[17]高光珠,李忠武,余理富等.归一化互相关系数在图像序列目标检测中的应用.计算机工程与科学,2005,27(3):38-40.Gao G Z,Li Z W,Yu L F,et al.Application of thenormalized cross correlation coefficient in image sequenceobject detection.Computer Engineering and Science(inChinese),2005,27(3):38-40.
[18]曾华霖,许德树.最佳向上延拓高度的估计.地学前缘,2002,9(2):499-504.Zeng H L,Xu D S.Estimation of optimum upwardcontinuation height.Earth Science Frontiers(in Chinese),2002,9(2):499-504.
[19]孟小红,刘国锋,陈召曦等.基于剩余异常相关成像的重磁物性反演方法.地球物理学报,2012,55(1):304-309.Meng X H,Liu G F,Chen Z X,et al.3-D gravity andmagnetic inversion for physical properties based on residualanomaly correlation.Chinese J.Geophys.(in Chinese),2012,55(1):304-309.
1)实际资料来源于中国石油天然气股份有限公司吉林分公司(吉林油田).
3)刘财,张凤旭.吉林省南部重磁资料处理与解释(成果报告).吉林大学,2011.