三维地电结构下CSAMT分辨能力研究  

CSAMT resolution in 3D geoelectric structures

作　　者：王显祥[1] 底青云[1] 唐静[1] 郭海峰[2] 

机构地区：[1]中国科学院地质与地球物理研究所中国科学院工程地质力学院重点实验室,北京100029 [2]河北省电力勘测设计研究院,石家庄050031

出　　处：《地球物理学进展》2014年第5期2258-2265,共8页Progress in Geophysics

基　　金：国家重大科研装备研制项目"深部资源探测核心装备研发"(ZDYZ2012-1)-05子项目"多通道大功率电法勘探仪";国家自然科学基金项目(4117411)联合资助

摘　　要：随着CSAMT法精细结构探测应用需求的日益增多,其相关分辨率的研究逐渐成为研究的热点.在CSAMT三维地质结构数值模拟中,积分方程法因只在异常体处剖分,具有计算速度快、求解精度高等优点.本文首先介绍了三维积分法的原理,然后利用3D积分方程正演程序模拟计算了四种情况下的模型:同一埋深不同体积的模型、同一大小不同埋深的模型、同一大小同一埋深情况下改变其与背景电阻差异大小的模型和两个相同异常体相隔不同距离的模型.除此之外,还设计了一个由岩浆的交代或围岩蚀变作用而在岩浆周围成矿的典型模型.通过这些模型的数值模拟,得出了以下结论:异常体的体积、异常体埋深、异常体与背景电阻率差异对异常响应特征影响明显,并且从数值模拟结果中可以看出CSAMT可以很好的将相距一定距离的多个异常体分辨出来,其对低阻体具有较强的探测能力,而对高阻体的勘探能力相对较弱,这可能对在高阻体边缘寻找金属矿床具有一定的优势.As CSAMT method being used widely,its resolution has become a hotspot that people have to face and urgently deal with.In the CSAMT＇s numerical simulation of threedimensional geological structure,integral equation method only focuses on the abnormal domain,therefore faster processing speed and higher accuracy could be obtained.This paper firstly introduced the 3D integral equation method,then four models were employed using the program of 3D integral equations：based on the parameters of different volumes,depth,resistivity anddistances.As for mineral deposit for magmatic intrusion,the typical model was designed and computed.According to these simulations conducted above,it showed that the anomalous result is proportional to the volume of abnormal body and the resistivity differences between abnormal body and surrounding,and inversely proportional to the square of the distances from the center of the abnormal body to the sounding point.Furthermore,multiple close abnormal bodies can be distinguished well from the results of CSAMT numerical simulation,and the metallic minerals around high-resistivity bodies can be detected very well.

关 键 词：可控源 积分方程 分辨率 电磁勘探 

分 类 号：P631[天文地球—地质矿产勘探]