本文提出了一种井间低频电磁波测量方法 ,用于重建地下介质电阻率分布。首先选择一个位于井轴上的垂直磁偶极子作为场源 ,并假设参与计算的介质相对于偶极子轴是轴向对称的 ,这样可将模型作为二维问题处理。文中每次进行迭代涉及的正演模拟把总场分为背景场和散射场两部分 ,背景场使用解析法计算 ,而散射场使用 FFM数值近似方法计算 ;在反演计算时使用正则化最小二乘拟合反演技术 ,从跨井电磁波测量资料中重现地下介质的电阻率剖面 ,使用互换原理来处理格林函数的计算以得到电磁响应对电阻率的偏数 ,从而改善了计算精度和工作效率。模型重现的结果表明 ,这种电磁成像方法同时适用于高电阻率对比度模型。像的垂直分辨率随频率的提高而改善 ,而水平分辨率则与频率、收发间距和异常体到钻孔的距离等因素有关。数值模拟的结果表明 ,最佳工作频率则应根据围岩电阻率进行选择 This paper presents a cross-well low-frequency electromagnetic wave measurement method used to reconstruct the distribution of the resistivity of the underground medium. First, select a vertical magnetic dipole on the well axis as the field source and assume that the medium involved in the calculation is axially symmetric with respect to the dipole axis, thus treating the model as a two-dimensional problem. The forward modeling involved in each iteration in this paper divides the total field into two parts: the background field and the scattering field. The background field is calculated by analytic method, while the scattering field is calculated by using the FFM numerical approximation method. In the inversion calculation, Using the fitting inversion technique, the resistivity profile of the subterranean medium is reproduced from the cross-well electromagnetic wave measurement data, and the interaction principle is used to process the calculation of the Green’s function to obtain the bias of the electromagnetic response to the resistivity so as to improve the calculation accuracy and Work efficiency. The results of the model reconstruction show that this electromagnetic imaging method is suitable for both high resistivity contrast models. The vertical resolution of the image is improved with increasing frequency, while the horizontal resolution is related to the frequency, distance between the transceiver and the body and the distance from the body to the borehole. The numerical simulation results show that the best working frequency should be selected according to the resistivity of surrounding rock