基于磁异常的目标体定位反演方法研究

发布时间：2019-03-07 14:03

【摘要】：磁法测量是一种应用较为广泛的地球物理勘探方法，可以测量总场及其在笛卡尔坐标系下三个方向的梯度张量场，，具有高效率和高精度探测特性。磁梯度张量作为一种新兴的地球物理观测手段逐渐成为磁测技术的研究热点，其能提供地质体在不同方向上的异常信息，可更准确地描述地质体的特征。由于磁梯度张量数据在磁性目标体不同方向上呈现出的信息量极为丰富，被应用于磁性目标体的识别和定位，例如隐伏地质体勘探、UXO探测、反潜等。实现目标体的空间定位，是磁测研究的主要目的之一。通过研究磁总场及其梯度张量场数据和相应的反演方法，实现目标体高精度、快速定位。本论文首先结合当前已有磁测搭载平台，分析了磁测采集系统的研究进程，分别对航空磁测、海洋磁测、卫星磁测及磁梯度张量测量的发展现状进行了详细综述，评价不同系统间的优势与不足，对比国内外研究差距，以提高磁测系统集成能力和目标体探测能力，为更好地利用有效精度内的磁测仪器以及实现多手段、多途径、快速测量提供相关指导。为更好地研究浅层目标体磁性特征，本文对金山地区UXO磁测数据进行了处理与解释。研究发现，中值滤波对在浅层磁异常数据处理中效果较好，滤除条带状背景噪声的同时很好地保留了UXO异常体有效信息。再利用Oasis Montaj下的UXParameter Determination模块对疑似目标体进行定位和标记。利用改进的欧拉反褶积法对抽取出的UXO磁异常进行深度反演，结合解析信号所圈定的UXO异常中心区域进行约束，计算该区域内反演深度的平均值，提高了反演的准确性。本文对磁梯度张量单点定位法在噪声环境及多目标体条件下定位情况进行了研究，通过对多点定位结果的概率分析可以提高确定目标体定位准确度，有效地解决了高噪声和多目标体条件下定位结果过于发散的问题。本文成功将该方法应用在某海域磁测数据，准确地定位到水下磁性体的空间位置。为提高磁梯度张量数据的边界识别的精度，本文采用计算张量特征值及其频率域垂直导数的方法，对磁性目标体进行水平定位和边界识别。通过对比解析信号法、倾斜角法和Theta图法，该方法所呈现边界信息更为清晰，在噪声环境下适用性强。在安徽庐枞地区磁异常数据处理中，该方法能很好地圈定出了庐枞火山岩盆地的边界位置。
[Abstract]:Magnetic survey is a widely used geophysical exploration method. It can measure the total field and its gradient tensor field in three directions under Cartesian coordinate system. It has high efficiency and high precision. As a new geophysical observation method, magnetic gradient Zhang Liang has gradually become a research hotspot of magnetic survey technology. It can provide abnormal information of geological bodies in different directions, and can more accurately describe the characteristics of geological bodies. Because the magnetic gradient Zhang Liang data presents abundant information in different directions of magnetic objects, it has been applied to the identification and location of magnetic objects, such as hidden geological body exploration, UXO detection, anti-submarine and so on. It is one of the main purposes of magnetic measurement research to realize the spatial location of the target body. By studying the data of the total magnetic field and its gradient tensor field and the corresponding inversion method, the high precision and fast positioning of the target are realized. Firstly, the research progress of magnetic data acquisition system is analyzed, and the development status of aeromagnetic survey, marine magnetic survey, satellite magnetic survey and magnetic gradient Zhang Liang survey are summarized in detail. The advantages and disadvantages of different systems are evaluated, and the research gaps at home and abroad are compared in order to improve the integration ability of magnetic measurement system and the detection ability of target body, in order to make better use of effective precision magnetic measuring instruments and to realize multi-means and multi-ways. Rapid measurement provides guidance. In order to better study the magnetic characteristics of shallow target body, the UXO magnetic data in Jinshan area are processed and interpreted in this paper. It is found that the median filter has a good effect on the processing of shallow magnetic anomaly data, while filtering the strip background noise, the effective information of the UXO anomaly body is well preserved. Then the UXParameter Determination module under Oasis Montaj is used to locate and mark the suspected target. Using the improved Eulerian deconvolution method, the depth inversion of the extracted UXO magnetic anomaly is carried out. Combined with the constraint of the central region of the UXO anomaly delineated by the analytical signal, the average of the inversion depth in the region is calculated, and the accuracy of the inversion is improved. In this paper, the magnetic gradient Zhang Liang single-point positioning method is studied under the condition of noise and multi-target body. The accuracy of locating target body can be improved by probability analysis of multi-point positioning results. It effectively solves the problem of excessive divergence of location results under the condition of high noise and multi-target. In this paper, the method is successfully applied to the magnetic data of a certain sea area to locate accurately the space position of the underwater magnetic body. In order to improve the accuracy of boundary recognition of magnetic gradient Zhang Liang data, this paper uses the method of calculating Zhang Liang eigenvalue and its vertical derivative in frequency domain to locate and identify magnetic objects horizontally. By comparing analytic signal method, tilt angle method and Theta diagram method, the boundary information presented by this method is more clear and has strong applicability in noisy environment. In the data processing of magnetic anomalies in the Luzong area of Anhui Province, the boundary position of the Luzong volcanic basin can be well delineated by this method.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.2

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