2.5-D Inversion of Advanced Detection Transient Electromagnetic Method in Full Space

Abstract

The transient electromagnetic method (TEM) can be applied in detecting coal mining heading face with multiple angles. However, a 1-D inversion scheme cannot fit this kind of multi-angle data-receiving system well, nor reducing detection accuracy. Developing a 2.5-D inversion method is necessary for TEM multi-angle data. The expressions of the vertical and horizontal magnetic dipole source at any position in the layered medium are derived on the basis of the potential function and the boundary conditions of the electromagnetic field. Then, the electromagnetic field of the magnetic dipole source with multiple angles can be obtained through vector stacking. A low-resistance anomalous body above the roof in front of a roadway excavation was identified by applying a 2.5-D least square inversion method in mine TEM-advanced detection to verify the effectiveness of the inversion method. Moreover, the method was used to detect water inrush from one side of the roadway in a coal mine in Shandong Province, China. Furthermore, the inversion results were verified by the information of boreholes and excavation. The proposed 2.5-D inversion method has a higher interpretation accuracy and resolution than the 1-D inversion method of the model and the measured data. INDEX TERMS Mine transient electromagnetic method, advanced detection, arbitrary angle field source, 2.5-dimensional inversion, damped least squares method.

Fine detection and analysis of hidden Karst in wellsite with quasi-three-dimensional TDEM based on lateral constraint

“…Geophysical exploration is an economical, rapid, non-destructive and efficient means, among which high-density electrical method, geological radar method, audio magnetotelluric method, time domain electromagnetic method and surface nuclear magnetic resonance method are widely used in the detection of adverse geological bodies (karst caves, underground rivers, cracks, underground goaf, faults and geological disaster investigation) [5][6][7][8][9][10][11]. With the digitization and intellectualization of instruments and the development of processing and interpretation technology, the scope of geological problems that can be solved is constantly expanding [12][13][14][15]. The time domain electromagnetic method (TDEM) uses a grounded conductor or ungrounded loop to send a pulsed electromagnetic field underground.…”

“…However, these methods are based on single-point one-dimensional inversion or imaging, the continuity of inversion section is poor, only approximate geological understanding can be obtained, and the late signal is weak, deep area is greatly affected by noise, and the geological body is not easy to implement. Although the second and third inversion of TDEM have made great progress [12,16,[27][28][29][30][31], they have not been popularized and applied due to the large amount of calculation and the limitation of computing platform. Therefore, considering the poor continuity, strong heterogeneity and difficult identification of hidden karst geological body, based on the regularized one-dimensional inversion, this paper introduced horizontal constraint inversion to simulate three-dimensional, so as to suppress the unreasonable phenomena of inversion model mutation caused by single point noise and effectively identify hidden karst geological body in well site.…”

A Review of Geophysical Modeling Based on Particle Swarm Optimization

“…The main applications of PSO to the geophysical inverse problem include the interpretation of: vertical electrical sounding (VES) (Fernández-Álvarez et al 2006 ; Fernández Martínez et al 2010a ; Pekşen et al 2014 ; Cheng et al 2015 ; Pace et al 2019b ); gravity data (Yuan et al 2009 ; Pallero et al 2015 , 2017 , 2021 ; Darisma et al 2017 ; Jamasb et al 2019 ; Essa and Munschy 2019 ; Anderson et al 2020 ; Essa and Géraud 2020 ; Essa et al 2021 ); magnetic data (Liu et al 2018 ; Essa and Elhussein 2018 , 2020 ); multi-transient electromagnetic data (Olalekan and Di 2017 ); time-domain EM data (Cheng et al 2015 , 2019 ; Santilano et al 2018 ; Pace et al 2019c ; Li et al 2019 ; Amato et al 2021 ); MT data (Shaw and Srivastava 2007 ; Pace et al 2017 , 2019a , c ; Godio and Santilano 2018 ; Santilano et al 2018 ) and radio-MT data (Karcıoğlu and Gürer 2019 ); self-potential data (Santos 2010 ; Pekşen et al 2011 ; Göktürkler and Balkaya 2012 ; Essa 2019 , 2020 ) and induced polarization (Vinciguerra et al 2019 ); Rayleigh wave dispersion curve (Song et al 2012 ) and full waveform inversion (Aleardi 2019 ). …”

“…time-domain EM data (Cheng et al 2015 , 2019 ; Santilano et al 2018 ; Pace et al 2019c ; Li et al 2019 ; Amato et al 2021 );…”

Multiple-Transmit Focusing for the Nondestructive Testing of Downhole Casings Based on Borehole Transient Electromagnetic Systems

“…Owing to their significant feature of accessibility to targets, borehole measurements have been widely used in many research fields, such as mineral detection [1], [2], oil & gas exploration [3], [4], and geotechnical and environmental investigations [5]. In the field of the nondestructive testing (NDT) of downhole casings, a borehole transient electromagnetic (TEM) system enables highly accurate measurements using the transient (pulsed) properties of eddycurrents [6]- [8].…”