物探与化探
物探與化探
물탐여화탐
GEOPHYSICAL AND GEOCHEMICAL EXPLORATION
2014年
1期
120-124
,共5页
广域电磁法%Eφ视电阻率%E-Eφ装置
廣域電磁法%Eφ視電阻率%E-Eφ裝置
엄역전자법%Eφ시전조솔%E-Eφ장치
wide field electromagnetic method%Eφ apparent resistivity%E-Eφ array
在准静态极限条件下,利用水平电偶极子电磁场电分量的表达式,讨论了Eφ分量、Ex 分量的幅值范围。在均匀半空间的条件下水平电场Eφ分量、Ex 分量幅值范围不同,测量Eφ分量计算广域视电阻率可以扩大野外的观测扇区,减小施工成本。数值计算结果表明广域电磁法也有近区的存在。通过二层地电模型的正演理论曲线的讨论以及野外实测数据的对比与分析,发现E-Eφ分量定义的广域视电阻率受观测角度的影响较E-Ex 广域视电阻率小,在相应的观测扇区内不会发生视电阻率曲线畸变。
在準靜態極限條件下,利用水平電偶極子電磁場電分量的錶達式,討論瞭Eφ分量、Ex 分量的幅值範圍。在均勻半空間的條件下水平電場Eφ分量、Ex 分量幅值範圍不同,測量Eφ分量計算廣域視電阻率可以擴大野外的觀測扇區,減小施工成本。數值計算結果錶明廣域電磁法也有近區的存在。通過二層地電模型的正縯理論麯線的討論以及野外實測數據的對比與分析,髮現E-Eφ分量定義的廣域視電阻率受觀測角度的影響較E-Ex 廣域視電阻率小,在相應的觀測扇區內不會髮生視電阻率麯線畸變。
재준정태겁한조건하,이용수평전우겁자전자장전분량적표체식,토론료Eφ분량、Ex 분량적폭치범위。재균균반공간적조건하수평전장Eφ분량、Ex 분량폭치범위불동,측량Eφ분량계산엄역시전조솔가이확대야외적관측선구,감소시공성본。수치계산결과표명엄역전자법야유근구적존재。통과이층지전모형적정연이론곡선적토론이급야외실측수거적대비여분석,발현E-Eφ분량정의적엄역시전조솔수관측각도적영향교E-Ex 엄역시전조솔소,재상응적관측선구내불회발생시전조솔곡선기변。
Using the electromagnetic fields of a horizontal electric dipole electric component expression, this paper discussed the Ex and Eφ components which have different amplitude ranges, and propose a new apparent resistivity of wide field electromagnetic defined by Eφ component. The authors also studied the characteristics of the apparent resistivity of wide field. Under the condition of the homogene-ous half space, the measurement of Eφ components can expand the field observation sector and reduce the construction cost. Through studying the two-layer model of the forward theoretical curves, the authors have found that the wide field apparent resistivity defined by Eφ component has much smaller observation angle than Ex mode, corresponding to the observed sector where no apparent resistivity curve distortions occur. By calculating apparent resistivity defined by wide field Eφcomponent of type H and type K model, the authors have found that wide field electromagnetic method is more sensitive to low resistance. The numerical results show that the wide field e-lectromagnetic method also has the near-zone.