Layered Multi-Exponential Inversion Method on Surface Magnetic Resonance Sounding Dataset
详细信息
- 责任者：Lin Tingting (Key Laboratory of Geo-Exploration Instrumentation ; Ministry of Education ; Jilin University ; Changchun 130021 ; China) ; Hui Fang
- 刊名：Chinese Journal of Geophysics
- 出版年：2013
- 卷期：56(8)
- 关键词：磁测深法 ; magnetic sounding
- 页码：p.2849-2861
- 图表：10 illus., 4 tables, 24 refs.
- 分类号：1600
- issnNo：ISSN0001-5733
- isbnNo：CN11-2074/P
摘要
Smooth inversion and block inversion are two main methods for surface magnetic resonance sounding(MRS) at present,which can construct water content and average effective pore size of aquifer through initial amplitudes and mean relaxation times,respectively.However,these inversion methods are limited in porous geological environment and in some case the interface of aquifers can not be portrayed clearly due to the loss of valid information during mono-exponential fitting.Aiming at these problems,we studied multi-exponential inversion method,which is found to solve inversion problem on the basis of MRS signal inherent multi-exponential behavior,by taking the entire MRS signal datasets into account in this paper.The multi-exponential MRS inversion of porous geological environment was realized through decomposing the relaxation time,deducing a new magnetic resonance forward kernel function and then calculating the functional minimum equation,which directly estimates the partial water content distribution and thus provides both the water content and relaxation time depth distribution.In order to get the fast and stable result,layered inversion model is referenced and the optimized inversion is proposed based on inequality constrain of the trust region algorithm.The inversion examples for synthetic data and field data from Baicheng city Sifangtuozi show that this method is better than smooth inversion and block inversion.We can get more accurate water content distribution and depict porous geological structure with high efficiency of inversion calculation.This paper confirms that the inversion has properties of accuracy,applicability and extensibility,which provide a new thought and method for surface magnetic resonance sounding.