多项式等效源反演方法研究

发布时间：2018-05-30 14:45

本文选题：等效源 + 多项式　；参考：《中国地质大学(北京)》2015年硕士论文

【摘要】：航磁数据一般点线距较大,不能对其进行网格化,因为这样会带来误差。而在磁异常数据后期处理过程中,如延拓、化极、求导等,上述误差会依然存在,甚至变大。因此,直接对测线数据进行场变换处理。由于航磁数据一般不规则,不能通过快速傅里叶变换在频率域进行处理,只能在空间域进行场转换,这时,等效源方法便是一种很好的选择。等效源反演技术的传统方法是对观测数据进行线性反演计算,得到可以模拟实际场源的等效源模型。这样用等效源来代替真正的复杂地质体场源,就可以在重磁数据后期处理过程中很方便地作各种场的变换,如延拓、化极、求导等。本文的主要研究工作和成果如下:(1)研究了传统等效源方法,编写了此方法的程序,并对模型数据进行反演。然后分析了传统方法中的不足,如计算效率低、求解参数个数多、空间占用大等问题。(2)为了解决等效源反演方法中计算效率低、求解参数个数多、空间占用大等问题,论文研究了多项式等效源反演方法,编写了此方法的程序,并对模型数据进行反演。实验发现复杂地质体情况下,如果只用一个多项式来表达等效源的物性,即使提高多项式阶次,也不能达到很好的反演效果。于是,我们提出了分段多项式反演的方法。(3)简单的分段多项式反演方法会使得反演结果不连续,只是将结果简单地拼在了一起。为解决这个问题,本文中提出了窗口滑动覆盖多项式等效源反演方法,并在每段采取不同的反演阶次。取一范围的数据,进行多项式等效源反演,反演完后保留中间一部分等效源结果,然后再进行滑动计算。互相覆盖滑动多项式等效源反演计算的方法可以提高反演的精度。(4)新方法的提出,在一定程度上提高了计算效率、减少了求解参数个数、降低了内存消耗,是一种很好的方法。
[Abstract]:Aeromagnetic data can not be gridded because of the error due to the large distance between points and lines. In the post-processing of magnetic anomaly data, such as continuation, polarization, derivation and so on, the above errors will still exist or even become larger. Therefore, the field transformation of the line data is carried out directly. Because aeromagnetic data are usually irregular, they can not be processed in frequency domain by FFT, but can only be converted in spatial domain. In this case, the equivalent source method is a good choice. The traditional method of equivalent source inversion is to calculate the observed data by linear inversion, and to obtain the equivalent source model which can simulate the actual field source. In this way, the equivalent source can be used to replace the real field source of the complex geological body, so that the transformation of various fields, such as extension, polarity, derivation and so on, can be made conveniently during the post-processing of gravity and magnetic data. The main work and results of this paper are as follows: (1) the traditional equivalent source method is studied, the program of this method is compiled, and the model data is retrieved. Then the shortcomings of the traditional methods are analyzed, such as low computational efficiency, large number of parameters, large space occupation, etc.) in order to solve the problems of low computational efficiency, large number of parameters and large space occupation in the method of equivalent source inversion, etc. In this paper, the polynomial equivalent source inversion method is studied, the program of this method is compiled, and the model data is inversed. It is found that in the case of complex geological bodies, if only one polynomial is used to express the physical properties of the equivalent source, even if the polynomial order is increased, the inversion effect can not be achieved. Therefore, we put forward the piecewise polynomial inversion method. 3) the simple piecewise polynomial inversion method will cause the inversion results to be discontinuous, but simply put the results together. In order to solve this problem, a window sliding cover polynomial equivalent source inversion method is proposed in this paper, and different inversion order is adopted in each section. Taking a range of data, the polynomial equivalent source inversion is carried out, and the middle part of the equivalent source result is retained after inversion, and then the sliding calculation is carried out. The method of reciprocal covering sliding polynomial equivalent source inversion can improve the precision of inversion. It is a good method to improve the efficiency of calculation, reduce the number of parameters and reduce the memory consumption to a certain extent.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.2

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