张量CSAMT电磁场分布规律和应用技术研究

发布时间：2018-07-07 15:30

本文选题：张量可控源 + 场源装置类型　；参考：《中国矿业大学》2017年硕士论文

【摘要】：在电磁法领域中,一直都是用标量的方式探测地下构造,标量测量在探测复杂构造地质体时不能反映其各向异性,而张量探测方式可以向地下发射不同极化方向和类型的矢量场,能够解决地质体各向异性的问题,本文针对张量CSAMT的基础理论和方法技术进行了研究,对张量CSAMT的应用具有指导意义。本文首先对CSAMT发射源不同的装置形式进行了研究,通过理论公式推导,数值模拟的方法分别研究了单偶极子源、L型源、十字型源和旋转矢量源的电磁场分布规律,并对它们的有效观测区域进行了圈定和分析,其中标量源电磁场辐射花样图呈花瓣状分布,因此探测区域在一定角度范围内存在盲区;通过理论公式推导得出L型源和十字型源电磁场分布满足矢量合成的原则,数值模拟所得的电磁场分布辐射花样图相当于水平方向的单一偶极子源整体逆时针旋转了45°和135°,验证了理论公式推导的正确性,而其观测范围内的盲区相当于两个标量源的叠加;在此基础上,对比旋转矢量源辐射花样图和电流矢量图,发现旋转矢量源可实现360°张角范围内电磁波全方位覆盖,其观测范围内不存在盲区;设计理论地电模型,进行张量—维数值模拟,总结各种地电模型张量阻抗和向量以及视电阻率的变化特征,并在此基础上模拟了背斜和向斜地层模型的视电阻率二维分布,对比模拟结果可知张量CSAMT对模型形态反映效果良好。最后结合张量CSAMT在采空区、硫化矿床、金属矿探测中的应用实例,通过对比其和标量CSAMT及其他物探方法的探测结果可知在一维层状电性结构条件下,张量测量与标量测量的找矿效果相近;在电性结构复杂情况下,张量测量可以测得张量阻抗,能够对地质体各向异性进行分析,从而更精确的反映地下地质体分布形态,并且在分辨率和克服近区畸变以及噪声干扰方面优于标量测量。
[Abstract]:In the field of electromagnetic method, the underground structure is always detected by scalar method. Scalar measurement can not reflect the anisotropy of complex tectonic geological body. However, the Zhang Liang detection method can emit vector fields in different polarization directions and types into the ground, which can solve the problem of anisotropy of geological bodies. In this paper, the basic theory and technique of Zhang Liang CSAMT are studied. It has guiding significance for the application of Zhang Liang CSAMT. In this paper, the different device forms of CSAMT emission source are studied, and the electromagnetic field distribution of single dipole source, cross source and rotation vector source are studied by theoretical formula derivation and numerical simulation method, respectively. The effective observation area is delineated and analyzed. The electromagnetic radiation pattern of scalar source is petal-like, so there are blind areas in a certain range of angles. By deducing the theoretical formula, the electromagnetic field distribution of L-type source and cross-type source satisfies the principle of vector synthesis. The radiation pattern of electromagnetic field distribution obtained by numerical simulation is equivalent to that of a single dipole source in horizontal direction. The whole counterclockwise rotation of the source is 45 掳and 135 掳respectively, which verifies the correctness of the derivation of the theoretical formula. The blind area in its observation range is equivalent to the superposition of two scalar sources. On this basis, by comparing the radiation pattern of the rotating vector source with the current vector diagram, it is found that the rotating vector source can achieve the omnidirectional coverage of electromagnetic wave in the 360 掳angle range. The theoretical geoelectric model is designed, the Zhang Liang dimensional numerical simulation is carried out, and the variation characteristics of Zhang Liang impedance, vector and apparent resistivity of various geoelectric models are summarized. On this basis, the two-dimensional distribution of apparent resistivity of anticline and syncline stratigraphic models is simulated. The comparison of simulation results shows that Zhang Liang CSAMT can reflect the shape of the model well. Finally, combined with the application of Zhang Liang CSAMT in the exploration of goaf, sulphide deposits and metal ores, it can be seen that under the condition of one-dimensional stratified electrical structure, by comparing the results with those of scalar CSAMT and other geophysical prospecting methods, In the case of complex electrical structure, Zhang Liang measurement can measure the Zhang Liang impedance and analyze the anisotropy of geological bodies, thus more accurately reflecting the distribution of underground geological bodies. It is superior to scalar measurement in resolution, near area distortion and noise interference.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P631.325

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