摘要
通过对含异常体的三维地电模型进行系统正演和分析,提出了一种地—井瞬变电磁异常体快速定位方法。在对含异常体的三维地电模型进行正演响应规律分析时发现:纯异常场的X、Y分量曲线零点以及Z分量曲线的极值点与异常体深度对应较好;当异常体的规模、电阻率、埋深发生改变时,X、Y分量曲线形态基本不变;当异常体方位发生变化时,X、Y分量曲线形态发生变化。在此基础上,提出地—井瞬变电磁异常体快速定位方法:首先,依据X、Y曲线的零点确定异常体所在深度;其次,依据X、Y分量曲线形态确定异常体所在象限(90°范围);最后,依据X+Y或者X-Y分量的曲线形态将异常体定位于井周45°范围内。数值试验显示本方法对不同方位异常体模型的定位结果均与设计模型吻合。采用陕北某矿区地—井瞬变电磁实测数据作进一步验证,本文方法推断的结果与实际吻合较好。
Through systematic forward modeling and analysis of a 3D geoelectric model containing anomalous bodies,this study proposed a rapid positioning method of anomalous bodies based on the ground-borehole transient electromagnetic(TEM)method.The analysis of the forward modeling response laws of the 3D geoelectric model containing anomalous bodies shows that the zero points of the X and Y component curves and the extreme points of the Z component curve of a pure anomaly field correspond well to the depths of the anomalous bodies;the morphologies of the X and Y component curves are basically unchanged when the sizes,resistivity,and burial depths of the anomalous bodies change but change when the orientations of anomalous bodies change.On this basis,this study proposed the following method to rapidly position anomalous bodies using the ground-borehole TEM method.First,determine the depths of anomalous bodies according to the zero points of the X and Y curves.Next,determine the quadrants(within 90°)of anomalous bodies according to the morphologies of the X and Y component curves.Finally,position anomalous bodies within 45°of boreholes according to the morphologies of the X+Y or X-Y component curves.Numerical experiments show that the positioning results of models of anomalous bodies with different orientations are consistent with those of the model designed in this study.As further verified using the ground-borehole TEM measured data of a mining area in northern Shaanxi,the inference that there is a water-filled goaf to the northwest of the borehole obtained using the method proposed in this study well agrees with the actual situation.
作者
赵友超
张军
范涛
姚伟华
杨洋
孙怀凤
ZHAO You-Chao;ZHANG Jun;FAN Tao;YAO Wei-Hua;YANG Yang;SUN Huai-Feng(Geotechnical and Structural Engineering Research Center,Shandong University,Jinan250061,China;Shandong Provincial Communications Planning and Design Institute,Jinan 250031,China;Xi'an Research Institute of China Coal Technology&Engineering Group,Xi'an 710077,China;Advanced Exploration and Transparent City Innovation Center,Shandong Research Institute of Industrial Technology,Jinan 250061,China)
出处
《物探与化探》
CAS
北大核心
2022年第2期383-391,共9页
Geophysical and Geochemical Exploration
基金
山东省自然科学基金项目(ZR2019MD20)
国家自然科学基金项目(42074145、42004056)。
关键词
地—井瞬变电磁
时域有限差分
三维正演
异常体定位
ground-borehole transient electromagnetic
time-domain finite difference
3D forward modeling
positioning of anomalous bodies
