A synthetic aperture for land controlled-source electromagnetic surveys

作     者：Zhang, Jifeng Huang, Rihua Feng, Bing 

作者机构：Changan Univ Sch Geol Engn & Geomat Dept Geophys Xian 710054 Peoples R China Zhenhai Urban Planning & Survey Res Inst Ningbo Ningbo 315200 Peoples R China 

出 版 物：《JOURNAL OF APPLIED GEOPHYSICS》 (应用地球物理学杂志)

年 卷 期：2020年第174卷第0期

页      面：103945-000页

核心收录：

学科分类：0819[工学-矿业工程] 07[理学] 0708[理学-地球物理学] 

基　　金：National Key R&D Program of China [2017YFC0602202] Emei-hanyang highway engineering research project [LH-HT-45] 

主　　题：Synthetic aperture Controlled-source electromagnetic method Deep exploration Weak information extraction 

摘      要：A controlled-source electromagnetic method with a synthetic aperture is proposed to improve the ability to detect a deep target body in the subsurface. First, we deduced the formulas of three-dimensional diffusion equations in the frequency domain, and gave the expression of synthetic aperture of the controlled-source electromagnetic array. An amplitude weighting coefficient, a phase shift coefficient, and a synthetic aperture range are selected based on model tests, and then, the optimum value of the error range is determined. A typical geo-electrical model is established, and the electric response, the normalized amplitude of the background field, and the apparent resistivity with and without a synthetic aperture are compared. The results show that a synthetic aperture can focus electromagnetic energy and enhance the electromagnetic response of the target body. This is beneficial when extracting weak anomaly information for a deep geo-electrical body, especially for a resistive target object. Finally, we apply the synthetic aperture to field data for gold ore in northern China, and the amplitude of a deep resistive anomaly is strengthened. This demonstrates that our method can be effectively applied to real field data processing using a synthetic aperture. (C) 2020 Elsevier B.V. All rights reserved.