A Joint Interpretation Method with Nuclear Magnetic Resonance and Transient Electromagnetic Data

摘要

In order to improve the accuracy of aquifer structure detection using the nuclear magnetic resonance (NMR) technique,combine the character that the NMR and the transient electromagnetic(TEM) technique are sensitive to the water content and the resistivity parameter respectively,we propose a joint interpretation method that inverse the NMR data base on the geoelectric model obtained by imaginary equivalent plate method using the TEM data.This paper describe the magnetism of nucleus and the basic theory of water detection by NMR technique,give out the computing way of free decay signal's initial amplitude.We get the fonctionelle respect to H-field according to the Maxwell equations,and convert it to finite element (FEM) equations by calculating its extreme point.By introducing pseudo-δ function and the divergence penalty term,we achieve the applying of the current source and avoid false solutions in 3d FEM problems.Considering the illness of sensitivity matrix and the noise in the measured data,we use a non-linear objective function contains penalty term,then optimize it with linearization technique.Finally,we verify the effectiveness of the joint interpretation method in this paper by model trial,the results show that the joint interpretation method achieved an accurate positioning and quantitative to water-bear body.