In crosswell observation of electromagnetic tomography, now there is no feasible way to calibrate the in situ radiation constant, while the effect of induced wave field always exists in observational data. Therefor...In crosswell observation of electromagnetic tomography, now there is no feasible way to calibrate the in situ radiation constant, while the effect of induced wave field always exists in observational data. Therefore the absorption coefficient obtained by a common used image reconstruction method is only a relative value. The consistency of tomograms in linked profiles inevitably is affected seriously. An improved equation involving the effect of induced wave field and an alternative tracing method to calculate the in situ radiation constant is proposed in the present paper. Based on the results from a series of parameter calibration performed in water and the experiments with rock samples, the standard meter readings of borehole electromagnetic systems, types EW—1 and JWQ—3, are accurately defined here. Additionally, frequency reduction and boundary smoothing of linked profiles are discussed. In research on groundwater prospecting in Tanggongta, Inner Mongolia, we used the above mentioned method and obtained the tomograms of linked profiles with good consistency. The absorption coefficient in the tomogram are not only reasonable and reliable, but also coincided with the result from rock parameter measurement. The depth, extension direction and water bearing structure of two aquifers were well detected. This result correctly guides hydrologic drilling there.展开更多
设计了一款基于STM32的矿用本安型瞬变电磁仪。发射部分通过发射双极性方波抑制工频及其多次谐波干扰;接收部分使用数据叠加、多次迭代实现采集信号的早、中、晚期信号的合成,提高动态范围及信噪比。井下实测表明接收电压由最大43.528 ...设计了一款基于STM32的矿用本安型瞬变电磁仪。发射部分通过发射双极性方波抑制工频及其多次谐波干扰;接收部分使用数据叠加、多次迭代实现采集信号的早、中、晚期信号的合成,提高动态范围及信噪比。井下实测表明接收电压由最大43.528 V下降至1.323μV,其接收动态范围>150 d B;与同类设备进行对比测试,结果与现场巷道人文设施以及出水情况相符,能够满足井下巷道超前探测对矿用瞬变电磁仪的要求。展开更多
文摘In crosswell observation of electromagnetic tomography, now there is no feasible way to calibrate the in situ radiation constant, while the effect of induced wave field always exists in observational data. Therefore the absorption coefficient obtained by a common used image reconstruction method is only a relative value. The consistency of tomograms in linked profiles inevitably is affected seriously. An improved equation involving the effect of induced wave field and an alternative tracing method to calculate the in situ radiation constant is proposed in the present paper. Based on the results from a series of parameter calibration performed in water and the experiments with rock samples, the standard meter readings of borehole electromagnetic systems, types EW—1 and JWQ—3, are accurately defined here. Additionally, frequency reduction and boundary smoothing of linked profiles are discussed. In research on groundwater prospecting in Tanggongta, Inner Mongolia, we used the above mentioned method and obtained the tomograms of linked profiles with good consistency. The absorption coefficient in the tomogram are not only reasonable and reliable, but also coincided with the result from rock parameter measurement. The depth, extension direction and water bearing structure of two aquifers were well detected. This result correctly guides hydrologic drilling there.
文摘设计了一款基于STM32的矿用本安型瞬变电磁仪。发射部分通过发射双极性方波抑制工频及其多次谐波干扰;接收部分使用数据叠加、多次迭代实现采集信号的早、中、晚期信号的合成,提高动态范围及信噪比。井下实测表明接收电压由最大43.528 V下降至1.323μV,其接收动态范围>150 d B;与同类设备进行对比测试,结果与现场巷道人文设施以及出水情况相符,能够满足井下巷道超前探测对矿用瞬变电磁仪的要求。
