大地电磁阻抗相位特性研究

发布时间：2018-03-30 18:16

本文选题：大地电磁测深　切入点：阻抗相位　出处：《成都理工大学》2015年硕士论文

【摘要】：大地电磁测深阻抗相位参数特性分析,这对于解决浅横向电性不均匀体导致区域构造中水平均匀的电场发生畸变问题和提高反演的准确性都显出较好的效果。本文对大地电磁阻抗相位的抗畸变特性和灵敏度特性进行初步研究。对阻抗相位张量、视电阻率和阻抗相位一维联合反演进行了理论模型的数值模拟和计算。初步讨论了阻抗相位张量在浅部不均匀体模型中抗畸变的作用和联合反演对于降低反演多解性的效果。论文对近地表非均匀体引起电场畸变进行了物理解释,对相位张量公式进行了推导和计算。用相位张量分析了加入电场畸变的单点模型,并且与传统的Swift方法进行了对比,当受到浅部小不均匀体的电场畸变时,Swift方法无法给出正确的电性主轴方位角。并且分析了浅部不均匀体的三维模型下的相位张量,在三维情况下,相位张量可以不受地表浅部不均匀体的影响,但能够反映该频率深度下电阻率横向变化最大的方向。论文根据均匀半空间的灵敏度函数和大地电磁响应曲线的斜率,对均匀半空间和层状模型(电阻率大于1Ω?m)的灵敏度进行了分析,对不同电阻率、频率和深度下的视电阻率和阻抗相位灵敏度做了对比。结果表明,阻抗相位资料的灵敏度要比视电阻率高。本文使用C++软件编写的视电阻率、阻抗相位和联合反演的算法。通过多种理论模型的反复试验和对比,认为相位反演在反演速度上更有优势,而视电阻率反演要比相位反演更稳定一些。当初始模型和真实模型相差太远时,视电阻率反演在大多数情况下会发散,而联合反演具有相位反演和视电阻率反演的共同优势,即在保持反演结果正确的前提下,其收敛速度也比较快。
[Abstract]:Analysis of magnetotelluric impedance phase parameters to solve the shallow lateral inhomogeneity leads to show good results in uniform electric field tectonic level distortion problem and improve the retrieval accuracy. This paper makes a preliminary study of the magnetotelluric impedance phase distortion resistance characteristics and sensitivity characteristics. The impedance phase tensor. The apparent resistivity and impedance phase inversion of one-dimensional numerical simulation and theoretical calculation model. Preliminary discussed the impedance phase tensor in shallow inhomogeneous bodies in the model of anti distortion and joint inversion of multiple solutions to reduce the inversion effect. The near surface inhomogeneities caused by electric field distortion is explained. The phase tensor formulas were deduced and calculated. Using the phase tensor analysis of single point model with electric field distortion, and with the traditional Swift method of By contrast, when the shallow small uneven body electric field distortion, electrical axis Swift method can not give the correct angle. And analyzed the phase tensor three-dimensional model of shallow inhomogeneous bodies under, in the three-dimensional case, the phase tensor can not the influence of uneven shallow surface, but can the direction of the lateral resistivity changes reflect the maximum frequency. According to the depth of the slope of the homogeneous half space sensitivity function and magnetotelluric response curve, the homogeneous half space and layered model (resistivity greater than 1? M) sensitivity analysis was carried out on different resistance, comparison of apparent resistivity and impedance phase sensitivity frequency and depth done. The results show that the sensitivity of impedance phase data than the apparent resistivity of high resistivity. This paper used to prepare the C++ software, and the impedance phase inversion algorithm. The theoretical model through a variety of The repeated test and contrast, think more in the inversion phase inversion speed advantage, and the apparent resistivity inversion than phase inversion is more stable. When the initial model and the real model is too far, the apparent resistivity inversion in most cases will diverge, and joint inversion with phase inversion and resistivity inversion of the common advantage, i.e. in the inversion results correct premise, its convergence speed is faster.

【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.325

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