广域电磁法E-E_φ视电阻率研究  

Study on apparent resistivity of wide field electromagnetic defined by E_φ component

作　　者：王宏宇[1,2] 程党性[3,4] 杨旭 

机构地区：[1]中南大学地球科学与信息物理学院,长沙410083 [2]西北有色地质勘查局,西安710054 [3]中国石油长庆油田分公司勘探开发研究院,西安710018 [4]低渗透油气田勘探开发国家工程实验室,西安710018

出　　处：《物探化探计算技术》2014年第1期9-15,共7页Computing Techniques For Geophysical and Geochemical Exploration

基　　金：国家自然科学基金项目(40827002)

摘　　要：利用水平电偶极子电磁场电分量的表达式,讨论了Ex分量、Eφ分量的幅值范围,提出了广域电磁法Eφ分量的视电阻率定义方法,初步研究了由Eφ分量定义的广域视电阻率的特点。在均匀半空间的条件下,水平电场Ex分量、Eφ分量幅值范围不同,测量Eφ分量可以扩大野外的观测扇区,减小施工成本。通过二层地电模型正演理论曲线的讨论,发现Eφ分量定义的广域视电阻率受观测角度的影响较比Ex方式小很多,在相应的观测扇区内不会发生视电阻率曲线畸变。通过H型、K型地电模型广域Eφ分量定义的视电阻率计算,结果表明,低阻中间层的反映情况比高阻中间层的好。数值计算结果表明,广域电磁法也有近区的存在。Using the electromagnetic fields of a horizontal electric dipole electric component expression,we discussed the Ex and E φ components which have different amplitude range,and propose a new apparent resistivity of wide field electromagnetic defined by E φ component.And we also study the characteristics of the apparent resistivity of wide field.Under conditions of the homogeneous half space,measurement of E φ components can expand the field observation sector,reducing construction cost. Through studying a two layers model of the forward theoretical curves,we found that the wide field apparent resistivity defined by E φ component has much smaller observation angle than Ex mode,corresponding to the observed sector there is no apparent resistivity curve distortions.By calculating apparent resistivity defined by wide field E φ component of type H and type K model, we found that wide field electromagnetic method is more sensitive to low resistance.The numerical results show that the wide field electromagnetic method also has nearly zone.

关 键 词：广域电磁法 Eφ视电阻率 电磁勘探 视电阻率 

分 类 号：P631.325[天文地球—地质矿产勘探]