【作者】 刘正；

【导师】 杨生；

【作者基本信息】 昆明理工大学 ， 地球探测与信息技术， 2010， 硕士

【摘要】 瞬变电磁法(TEM)是一种被广泛应用的地球物理勘探方法,而大定源回线装置又是TEM法中比较常用的一种,在施工中有着其特定优点。但是因为接收线圈和发射线圈之间的相对位置不固定,使得其数据处理难度很大。目前能够处理大定源回线的数据的软件并不是很多,而且操作繁琐,效果并不理想。本文利用1987年Raiche发布的大定源回线装置的响应公式,系统地分析大定源回线装置二次场响应的衰减特点,剖面曲线特点,其成果对于野外施工时参数的选择具有指导性的意义。消除关断效应是TEM数据处理的重要步骤之一,为了消除关断时间的影响,本文采用的方法是直接使用斜阶跃波响应响应值来计算视电阻率。为了快速地得到准确的斜阶跃波的理论响应值,本文利用阶跃波的响应公式和杜哈美尔积分推导了斜阶跃波的响应公式,并给出了详细的推导步骤。利用响应值计算视电阻率的过程是一个解隐函数的过程,在众多的算法中,本文选择了马奎特方法。考虑到使用全区响应值计算会出现多解的情况,本文采取将两个解全部求出,然后使用多种判别手段判别出合理解。为了实现这一设想,本文将马奎特法进行改进,使整个求解过程定能返回不同单调区间内的双解。在判别合理解的研究,中本文提出部分磁场判别法,并将此标准作为早期多解判别的主要别准,而晚期则使用了中心回线法作为主要判别标准,并以临近时间道的计算结果作为辅助判别标准。为了增加实测数据的可用性,作者开发了原始数据的整理模块,模块中采用3点平滑的方法对其进行降噪处理。最终开发出一套专门计算大定源回线数据的自编软件：瞬变电磁法大定源回线数据处理系统V1.0。通过设计用例的检验证明自编软件的算法有很强的适应性。最后在处理实测数据时取得了较为满意的效果。更多还原

【Abstract】 Transient Electromagnetic Methods(TEM) is one kind of the widely used geophysical prospecting methods. And the Large Fixed Transmitting Loop is a commonly used in TEM. But because the position of the reciever ralative to the transmitting loop can be changed, to process this kind of data is more difficult than other kind of data. Now, there is only a few specialized software can process the data of Large Fixed Transmitting Loop. Operating these software is dificult, and the result is not satisfactory yet.The oretical basis of this dissertation is the formula of the response of a large polygonal transmitting loop. With this formula that was which was published by Raiche in 1987, the characteristics of the response decay curves and the response section curve that is very important to indicate wild field sounding work, is systematically analyzed in this dissertation.It is an important step to eliminate the influence of ramp turn-off. In order to get accurate apparent resistivity, an analytic formula of ramp turn-off response of a large polygonal fixed loop is derived in this dissertation through the formula of step turn-off response and Duhamel integral formula.To get the apparent resistivity is a process of solution of an implicit function. In several common inversion algorithms, the Marquette inversion algorithm is choosen in this dissertation. The method to resolve the problem of multiple resolutions is to get all results of apparent resistivity first and then choose the reasonable result. In order to get all two apparent resistivity from one response value, the Marquette inversion algorithm is been modified to limit the search process in the monotone interval that contain the original value. The part of magnetic field is brought up in this dissertation as the main criterion to choose the reasonable result during early and intermediate stage, and the result calculated through central loop formula as the main criterion during later stage. Finally the auxiliary criterion is the near trace rensult.To improve the availability of wild field data, the quaulity control module is developed in which the three point filter method is used.Eventually a set of software, the large fixed transmitting Data Process System V1.0 is developed. The tests by self-designed test cases illustrate that the algorithms used in this software have very strong adaptability. A satisfactory result has been obtained in processing the measured data of HongQiling by this software.更多还原