【作者】 黄磊；

【导师】 汤井田；

【作者基本信息】 中南大学 ， 地球探测与信息技术， 2009， 硕士

【摘要】 可控源音频大地电磁法(CSAMT)是地球物理方法的重要组成部分。它是采用可以控制的人工场源的一种电磁法,其无论是在理论和应用方面都获得了成功。激发极化效应(IP)是电荷聚集在金属矿物和电解液的分界面上引起的,或者是黏土或孔隙束缚离子运动而引起的。IP是一种很有意义的参数,因为它可以用来探测有经济价值的硫化矿带的赋存特点和地质构造。但是,试图从CSAMT中提取有效的IP信息,国内外学者也进行了一定的研究,至今还没有明确的定论。本文首先回顾了从电磁法勘探中提取IP信息的发展,总结了国内外的研究现状。详细阐述了可控源音频大地电磁法的基本理论,并进一步探讨了电偶极子场的一维正演问题。接着研究了CSAMT中的IP影响,而且利用柯尔-柯尔模型模拟了可极化大地上CSAMT的IP效应。分析了电磁场各分量的特点,并且提出利用电场y分量来提取IP信息的可行性。初步尝试提取有效的IP信息。本文最后对三层介质上中间为极化层的水平电偶源视电阻率进行了理论计算。着重讨论了激电效应对于不同地电断面类型的影响,试图探求其变化规律,为CSAMT实际勘探资料中提取激电信息提供依据。通过以上研究表明,在可极化均匀大地上,IP效应对磁场y分量影响很小。而电场y分量能够很好的反应出IP效应。在层状介质中,从整体效果来讲,电场y分量定义的视电阻率对IP效应的反应好于其他定义的视电阻率。对于不同的地电断面,H型地电断面有利于发现中间极化层的存在。视电阻率对于低阻高极化层反应比较好。对于O型地电断面,中间极化层对视电阻率影响很小,很难反应出IP信息。更多还原

【Abstract】 The Controlled Source Audio-frequency Magnetotellurics(CSAMT) is an important part of the geophysics.It is one kind of controllable source electromagnetic method which both in theory and applications have been successful.Effect of induced polarization(IP) is the charge accumulation in metal minerals and dectrolytes caused by the boundary surface,or the clay or the hole fettering ion movement caused.IP is a significant parameter,because it can be used to detect the economic valuable sulphide ore zone characteristics and geological structure.But trying to extract from the CSAMT effective IP information,on which the domestic and foreign scholars have also conducted certain research,until now did not have the explicit conclusion.This article first reviewed the development of extracting the IP information from the electromagnetic prospecting and summarized the domestic and foreign research present situation.Elaborated in detail the CSAMT method’s basic theory, further discussed the forward problem of electromagnetic of the horizontal electrical dipole.Then has studied IP influence in the CSAMT,moreover model has simulated the CSAMT method’s IP effect using Cole-Cole model on the polarizable earth.Has analyzed the electromagnetic field various components characteristic,and proposed that regarding extraction the IP information using the electric field y component the new development.Preliminary attempted to extract effective IP information.Finally, we theoretical calculated the apparent resistivity of dectromagnetic of the horizontal electrical dipole under the three-layer which the middle layer is polarized.Discussed the influence of IP on differ section of resistivity,we attempted to seek its change rule.It provides grounds for extracting IP information from CSAMT.Through the above-mentioned studies have shown that on the polarizable earth,IP effect influences H_y very small.E_y can well reflect IP effect.In layered earth,from the overall effect is concerned,the apparent resistivity of the electric field y-component definition response to IP effect better than others.As to differ section of resistivity, H section of resistivity help to find the existence of middle layer polarization.Apparent resistivity for the low resistance layer high-polarization response is better.As to Q section of resistivity,the middle layer polarization influence apparent resistivity very much little,it is difficult to reflect the IP information.更多还原