地孔瞬变电磁超前探测异常体定位技术
Anomaly body advance detection technology of down-hole transient electromagnetic
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摘要: 地孔瞬变电磁法，是一种在地面布设发射回线，在钻孔中接收磁感应强度或者衰减电压三分量信号的探测技术，其观测系统置于钻孔中，可有效降低导电覆盖层的信号屏蔽及地面电磁干扰，接收更靠近异常体，可以获得比地面瞬变电磁法更强的异常响应，是探测深部隐伏地质体最有效的方法之一，可以考虑用于煤矿孔旁异常体的探测。根据等效涡流理论，地孔瞬变电磁探测中，异常体所产生的二次场，可以用等效电流环来表示，其感应磁场强度三分量Bx、By、Bz具有一定的指向性，通过交会Bx、By的合成矢量Bxy及Bx、Bz的合成矢量Bxz，可以大致获得电流环中心位置坐标，从而实现对异常体的定位，但合成Bxz在XZ平面交会结果存在误差。为此，提出了一种浮动系数矢量交会算法，通过计算水平圆形载流回线（电流环）的磁感应强度三分量Bx、By、Bz，分析其合成矢量Bxy及Bxz在XY、XZ平面的矢量分布特征，计算特征点处的Abs(By)/Bz作为参考值并构建系数库，对Bz分量进行系数修正后再与Bx分量进行矢量交会，可以准确计算出电流环中心位置在XZ平面的坐标。理论模型计算和物理试验结果表明：浮动系数矢量交会算法无需先验信息，可以快速、准确定位异常体的中心位置，是一种超前探测的有效方法。Abstract: Down-hole transient electromagnetic method is a kind of detection technology, which laid the transmitting loop on the ground and received three component signal of magnetic induction intensity or attenuation voltage in borehole. Its observation system is placed in the borehole, which can effectively reduce the signal shielding and ground electromagnetic interference of the conductive overburden.It can obtain stronger abnormal response than the ground transient electromagnetic method as the receiver closer to the abnormal body. It is one of the most effective methods to detect deep buried geological bodies which can be considered for detect abnormal bodies beside in coal mine. According to the equivalent eddy current theory, the secondary field produced by the abnormal body of Down-hole transient electromagneticcan be expressed by the equivalent current loop. The three components Bx、By、Bz of the induced magnetic field intensity have certain directivity. The coordinates of the current loop center position can be roughly obtained by intersecting the composite vector Bxy and Bxz. So it canlocate the position of the abnormal body. There are errors while intersect Bxz in XZ plane directly. In this paper, a floating coefficient vector intersection algorithm is proposed. We can obtain the vector distribution characteristics by calculating the three components of magnetic induction Bx By and Bz of the horizontal circular current loop (current loop) in the XY and XZ planes, calculatethe ABS(By)/Bz value at feature points and constructthe coefficient library. The coordinate of the current loop center position in XZ plane can be calculated accurately after correctthe vertical component Bz and intersect Bx component. The results of theoretical model calculation and physical experiments show that the floating coefficient vector intersection algorithm can quickly and accurately locate the abnormal body center without prior information. It is an effective method for advanced detection.
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期刊类型引用(3)
1. 韩晓冰，余思淼，梁冰洋，周远国. 基于DNN的矿井超前探测反演方法研究. 煤炭技术. 2023(03): 117-121 . 
百度学术
2. 吴群英，胡雄武，王宏科. 陕北矿区地下水资源地面瞬变电磁法探查实践. 煤炭科学技术. 2022(05): 208-215 . 本站查看
3. 智庆全，武军杰，王兴春，杨毅，张杰，邓晓红. 基于瞬变冲激时刻的地-井TEM快速定量解释方法. 煤田地质与勘探. 2022(07): 44-51 . 百度学术
其他类型引用(1)
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