激电中梯装置测量长方异常体的三维正演模拟及启示  

Three-dimensional forward and inspiration of abnormal cuboids under intermediate gradient way of IP method

作　　者：曹创华 邓专[1] 康方平 柳建新 童孝忠[3] CAO Chuanghua;DENG Zhuan;KANG Fangping;LIU Jianxin;TONG Xiaozhong(Geology Survey Institute of Hunan province,Changsha 410116,China;School of Geoseienees and Info Physics,Central South University,Changsha 410083,China;Hunan Key Laboratory of Non ferrous Resources and Geological Hazard Detection,Central South University,Changsha 410083,China)

机构地区：[1]湖南省地质调查院,长沙410116 [2]中南大学有色资源与地质灾害探查湖南省重点实验室,长沙410083 [3]中南大学地球科学与信息物理学院,长沙410083

出　　处：《物探化探计算技术》2018年第4期459-467,共9页Computing Techniques For Geophysical and Geochemical Exploration

基　　金：国家科技计划(2017YFC0602402;2017YFC0601506);湖南省国土厅科研项目(2018-04)

摘　　要：激电扫面实际测量时,由于测线布设方位和地下地质异常体的走向不尽一致,从而导致测量结果不同,给物探异常的解释带来了困难,甚至会引起误导,因此这里利用数值模拟方法,计算了激电中间梯度法测量条件下二度异常体在不同方位测量条件下的三维响应规律。首先实现了有限单元法三维正演的公式推导及其数值解求解;其次通过一维模型计算了数值解和解析解的误差,验证了本文中理论计算方法的有效性;最后设计了三维模型进行了理论计算,发现了激电中间梯度装置条件下二度异常体的走向和测量剖面方向成不同夹角时的面上响应规律。研究结果表明:随着两者夹角的增加,激电异常体的规模和形态逐渐与设计异常体一致,且两者夹角在60°~90°之间探测的实测数据较为可信。When IP（induced polarization method） scanning is applied to actual measurement, the direction of the lines＇ lay out is not always in accordance with the orientation of geological anomaly and thus the different results in that measurement cause difficulty in the interpretation of geophysical anomaly and even misleading. Therefore the author utilizes the numerical simulation method to calculate the three dimensional response of two dimensional body under different azimuth＇s measure ment when central gradient array method is used in IP. At first, the formula derivation and implementation steps of three di mensional forward model using the finite element method are fulfilled; Secondly through the one dimensional model to calcu late the error of numerical solution and analytical solution, the validity of theoretical calculation method in this paper is verified; At last, Designing three dimensional model for theoretical calculation, the author found response＇s law when the orientation of two dimensional body and the direction of measuremenfs profile have different angles under the condition of central gradient array method in the IP. The resuhs reveal that, with the increase of the angIe between the orientation of two dimensional body and the direction of measuremenfs profile, the size and shape of geological anomaly is consistent with the abnormal body designed in the modeling gradually and data in actual measurement that the angle of that two is between 60 and 90 is more reliable.

关 键 词：激电中间梯度法 有限单元法 测线方位 异常体走向 三维正演 

分 类 号：P631.3[天文地球—地质矿产勘探]