用新型模式匹配法计算地球物理中的电磁场

应用一种新型的数值模式匹配（NMM）理论快速完成了普通电阻率测井的数值模拟。在解析部分, 应用电磁场在层界面的连续性条件，对传统上所用的广义反射阵和透射阵理论进行了改进，推导出了上行波和下行波的递推关系，首次提出了界面转换阵的概念。这一方法避免了原NMM中复杂的求逆运算，思路简单，其物理意义也更明确。而且根据互易定理，用B-A-M电极系比A-M-N电极系计算速度提高了近一倍。用此方法对均匀介质、两层介质、三层介质进行了实验，并将其结果与解析法、原NMM方法和有限元方法进行了对比，验证了此方法的有效性。同时，这一思想对于三维模式匹配理论和计算成层介质中其他电探测方法的响应也具有借鉴意义。

An Improved NMM Method for Electro-Magnetic Field Calculation in Geophysics

A new type of numerical mode-matching(NMM) theory is applied into numerical simulation of common resistivity logs.In analytical section,by the continuity of interface between the adjacent layers in electromagnetic field,the traditional reflection and transmission matrixes is improved,and relationship between upgoing and down-going wave is derived.A new transition formula is firstly presented.The improved NMM method,avoiding complicated matrix inverse,is easy to understand and has concise physical meaning.Furthermore,according to reciprocal theory,the calculating speed for B-A-M is one time faster than that for A-M-N.By the experiments for two-layer and three-layer homogeneous media,this method is verified to be highly precise and effective comparing with FEM method and the previous NMM method.The core concept of new NMM is helpful to 3-dimension NMM and other geophysics method in stratum media.