Static displacement correction for frequency domain electromagnetic method based on second electrostatic field
LI Guo-Rui1, XI Zhen-Zhu2, 3, LONG Xia4
1.China Water Resources Beifang Investigation,Design & Research CO. LTD.,Tianjin 300222,China;; 2.School of Geosciences and Info-Physics,Central South University,Changsha 410083,China; 3.Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Central South University),Ministry of Education,Changsha 410083,China; 4.Hunan 5D Geological Science and Technology Co., Ltd.,Changsha 410205,China
Abstract:The static effect of the magnetotelluric sounding method is caused by stored charge on shallow layer electrical inhomogeneity by primary electric field. The induced second electric field caused by the accumulated charge is proportional to the primary electric field, and ratio coefficient K is only related to the electrical property of the underground media. The dielectric properties of the underground media are unchanged, and the K value is unchanged. Therefore, the method of artificial source is used to measure the total field of Et in power supply; the induced electric field E2 is measured in the off instantly, and then the proportion coefficient of K between the two data is calculated. K and measured electric field of the magnetotelluric sounding method are used to correct static effect, the finite element 2D MT forward modeling are employed to calculate the static effect produced by the underground electric uneven body, and K is used to correct static effect, thus achieving success. The results show that this method can effectively suppress the static effect and achieve the goal of static correction.
李国瑞, 席振铢, 龙霞. 基于实测积累电荷静电场消除静态效应的方法[J]. 物探与化探, 2017, 41(4): 730-735.
LI Guo-Rui, XI Zhen-Zhu, LONG Xia. Static displacement correction for frequency domain electromagnetic method based on second electrostatic field. Geophysical and Geochemical Exploration, 2017, 41(4): 730-735.