张军. 矿井孔中瞬变电磁探测异常响应特征模拟[J]. 煤田地质与勘探,2022,50(8):134−141. DOI: 10.12363/issn.1001-1986.21.11.0673
引用本文: 张军. 矿井孔中瞬变电磁探测异常响应特征模拟[J]. 煤田地质与勘探,2022,50(8):134−141. DOI: 10.12363/issn.1001-1986.21.11.0673
ZHANG Jun. Abnormal response characteristic simulation during transient electromagnetic detection in mine borehole[J]. Coal Geology & Exploration,2022,50(8):134−141. DOI: 10.12363/issn.1001-1986.21.11.0673
Citation: ZHANG Jun. Abnormal response characteristic simulation during transient electromagnetic detection in mine borehole[J]. Coal Geology & Exploration,2022,50(8):134−141. DOI: 10.12363/issn.1001-1986.21.11.0673

矿井孔中瞬变电磁探测异常响应特征模拟

Abnormal response characteristic simulation during transient electromagnetic detection in mine borehole

  • 摘要: 为了解决常规矿井瞬变电磁超前探测方法受矿井外界干扰影响较大,异常体探测定位不精确的问题,提出一种在井下钻孔中测量瞬变电磁场三分量信号的超前探测方法,对接收线圈所处水平面不同位置、异常体不同方位的异常响应特征进行数值模拟。分析钻孔瞬变电磁探测原理,进行钻孔发射线圈与接收线圈的试验设计以及施工设计,对均匀全空间模型、均匀全空间异常体模型、异常体位于钻孔不同方位的三分量异常场响应特征进行系统分析。在低阻异常体与线圈垂直时,X分量、Y分量、Z分量异常响应最大,随着低阻异常体逐渐平行于接收线圈法向,异常响应逐渐减小,当低阻异常体完全平行于接收线圈法向时,X分量、Y分量、Z分量异常响应最小。通过以上认识,可以根据钻孔径向不同象限位置的异常场三分量组合形态不同,判断异常体所在钻孔的方位。在以钻孔钻进方向为Z轴正方向,以孔口所在平面右向为X轴正方向,下向为Y轴正方向的坐标系下,钻孔瞬变电磁水平分量异常响应形态均为“近似正弦曲线”或“近似反向正弦曲线”形态,通过形态组合判定出孔旁异常体所在象限。通过这样的规律,可分析三维空间条件下异常体的空间位置及赋存状态。通过钻孔瞬变电磁超前探测异常响应特征的分析,可为钻孔瞬变电磁超前探测提供理论数据支持。

     

    Abstract: Conventional mine transient electromagnetic advance detection method is greatly influenced by the condition outside of the mine, which leads to the inaccurate location in anomalous body detection. In order to solve this problem, an advance detection method for measuring the three-component signals of the transient electromagnetic field in the down-hole borehole was proposed to carry out numerical simulation for the abnormal response characteristics from the different locations of the plane where the receiving coil is located and the different orientations of the anomalous body. The principle of borehole transient electromagnetic detection was analyzed, and the test design and construction design for the borehole transmitting coil and receiving coil were carried out. The uniform full-space model, uniform full-space anomalous body model, and the three-component abnormal field response characteristics when the anomalous body is located at different orientations of the borehole, were systematically analyzed. When the low-resistivity anomalous body was perpendicular to the coil, the abnormal response of components X, Y and Z was the maximum. As the low-resistivity anomalous body was gradually parallel to the normal direction of the receiving coil, the abnormal response was gradually reduced. When the low-resistivity anomalous body was completely parallel to the normal direction of the receiving coil, the abnormal response of the components X, Y and Z was minimum. Through this method, the orientation of the borehole where the anomalous body is located can be determined based on the principle that the abnormal field three-component combination forms are different for different quadrant locations in the radial direction of the borehole. In the coordinate system, where the drilling direction of the borehole was the positive direction of Z axis, the right direction of the plane where the borehole collar was located was the positive direction of X axis, and the downward direction was the positive direction of Y axis. All the abnormal response forms of the borehole transient electromagnetic horizontal component were either "approximately sine curves" or "approximately inverted sine curves". The quadrant where the anomalous body near the borehole can be determined through the form of combinations. Through such regularity, the spatial location and the occurrence status of the anomalous body under 3D spatial conditions. Through the analysis of the abnormal response characteristics during borehole transient electromagnetic advance detection, the theoretical data supporting the borehole transient electromagnetic advance detection can be provided.

     

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