| 对瞬变电磁测深几个问题的思考(三)——瞬变电磁场关断效应及全期视电阻率的普适算法 |
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| 引用本文： | 陈明生,许洋鋮.对瞬变电磁测深几个问题的思考(三)——瞬变电磁场关断效应及全期视电阻率的普适算法[J].煤田地质与勘探,2017,45(4):131-134. |
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| 作者姓名： | 陈明生 许洋鋮 |
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| 基金项目： | 国家自然科学基金项目（41374150） |
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| 摘 要： | 首先给出瞬变电磁（TEM）场卷积计算式，并将关断电流变化率函数看成冲击函数，垂直阶跃脉冲激发的场分量看成输入信号，卷积结果就是任意形状关断电流的TEM响应。把电流激发脉冲看成是许多垂直阶跃函数的叠加，通过叠加这些阶跃函数的响应求得任意电流脉冲激发的瞬变电磁响应。当已知TEM场的实测值和关断电流形状，就可按编程的方法计算全期视电阻率。文中给出了2个斜坡关断电流激发的电偶极源TEM垂直磁场算例，一个为均匀半空间的响应及其全期视电阻率，另一个为三层K型地电断面的响应及其全期视电阻率。
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| 关 键 词： | 电流激发脉冲 瞬变电磁场 关断效应 卷积 叠加 全期视电阻率 |
| 收稿时间： | 2016-08-06 |
Suitable algorithm of transient electromagnetic turn-off effects and whole-stage apparent resistivity |
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| Abstract: | Firstly the transient electromagnetic(TEM) field convolution was given, and change rate of turn-off current is taken as a impact function, the field component of vertical step pulse excitation as the input signal. The convolution result is TEM response of arbitrary shape turn-off current. The current excitation pulse is regarded as a superposition of many vertical step function. The transient electromagnetic response of arbitrary current pulse excitation is induced by the superposition of step function response. When the measured value of TEM field and the turn-off current form are known, whole-stage apparent resistivity can be calculated by the method of programming. The paper gives two examples on TEM vertical magnetic field of slope turn-off current excitation of electric dipole source, a response of uniform half-space and all-time apparent resistivity, a response to the three K-type geoelectric section and whole-stage apparent resistivity. |
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