Case History Illustrating Interpretation Problems in Transient Electromagnetic Surveys

1984 ◽  
Vol 15 (3) ◽  
pp. 155-167 ◽  
Author(s):  
R. J. Irvine ◽  
G. Staltari
Keyword(s):  
Case History ◽  
Transient Electromagnetic ◽  
Electromagnetic Surveys

Transient electromagnetic fields of a buried horizontal magnetic dipole

Geophysics ◽  
2016 ◽  
Vol 81 (6) ◽  
pp. E481-E491 ◽  
Author(s):  
Andrei Swidinsky ◽  
Misac Nabighian
Keyword(s):  
Electric Field ◽  
Magnetic Dipole ◽  
Time Domain ◽  
Major Axis ◽  
Secondary Response ◽  
Burial Depth ◽  
Transient Electromagnetic ◽  
The Earth ◽  
Smoke Ring ◽  
Electromagnetic Surveys

Electromagnetic surveys using a vertical transmitter loop are common in land, marine, and airborne geophysical exploration. Most of these horizontal magnetic dipole (HMD) systems operate in the frequency domain, measuring the time derivative of the induced magnetic fields, and therefore a majority of studies have focused on this subset of field measurements. We examine the time-domain electromagnetic response of a HMD including the electric fields and corresponding smoke rings produced in a conductive half-space. Cases of a dipole at the surface and buried within the earth are considered. Results indicate that when the current in the transmitter is rapidly switched off, a single smoke ring is produced within the plane of the vertical transmitter loop, which is then distorted by the air-earth interface. In this situation, the circular smoke ring, which would normally diffuse symmetrically away from the source in a whole space, is approximately transformed into an ellipse, with a vertical major axis at an early time and a horizontal major axis at a late time. As measured from the location of the transmitter, the depth of investigation and lateral footprint of such a system increases with burial depth. It is also observed that the electric field measured in the direction of the magnetic dipole only contains a secondary response related to the charge accumulation on any horizontal conductivity boundaries because the primary field is always absent. This field component can be expressed analytically in terms of a static and time-varying field, the latter term adding spatial complexity to the total horizontal electric field at the earth surface at early times. Applications of this theoretical study include the design of time-domain induction-logging tools, crossborehole electromagnetic surveys, underground mine expansion work, mine rescue procedures, and novel marine electromagnetic experiments.

scholarly journals Transient Electromagnetic Surveys for the Determination of Talik Depth and Geometry Beneath Thermokarst Lakes

2018 ◽  
Vol 123 (11) ◽  
pp. 9310-9323 ◽  
Author(s):  
A. L. Creighton ◽  
A. D. Parsekian ◽  
M. Angelopoulos ◽  
B. M. Jones ◽  
A. Bondurant ◽  
...  
Keyword(s):  
Thermokarst Lakes ◽  
Transient Electromagnetic ◽  
Electromagnetic Surveys

scholarly journals SkyTEM helicopter transient electromagnetic surveys of tailings dams

2012 ◽  
Vol 2012 (1) ◽  
pp. 1-4 ◽  
Author(s):  
James Reid ◽  
Niels Christensen ◽  
Kate Godber
Keyword(s):  
Transient Electromagnetic ◽  
Tailings Dams ◽  
Electromagnetic Surveys

Feasibility of Monitoring Hydraulic Connections between Aquifers Using Time-lapse TEM: A Case History in Inner Mongolia, China

2019 ◽  
Vol 24 (3) ◽  
pp. 361-372
Author(s):  
Kang Chen ◽  
Junyan Zhang ◽  
Guoqiang Xue ◽  
Hao Huang ◽  
Weiying Chen ◽  
...  
Keyword(s):  
Case History ◽  
Inner Mongolia ◽  
Electromotive Force ◽  
Time Lapse ◽  
Pumping Test ◽  
Pumping Tests ◽  
Transient Electromagnetic ◽  
Successful Case ◽  
Aquifer Properties ◽  
Hydrogeological Data

Hydraulic connections between aquifers is usually studied through hydrochemical analysis or by pumping tests. However, hydrochemical analyses are usually conducted in areas of variable lithology. In addition, the hydrogeological data obtained by drilling and pumping tests are typically insufficient to get 3D distributions of hydraulic head. In this paper, the time-lapse transient electromagnetic method (TEM) is used to image groundwater migration between aquifers in Inner Mongolia, China. First, 1D geophysical models of aquifers are generalized according to the hydrogeological conditions of the region, and the feasibility of detecting the multiple aquifers by TEM is analyzed and discussed. Then, the 2D models of aquifers pre- and post- pumping test are established based on the distribution of groundwater in the aquifers, and the variation law of induced electromotive force measured on the surface is analyzed. The simulation results show that significant time-lapse electromagnetic anomalies can be observed between pre- and post- pumping test and the variation in the induced electromotive force reaches a distinguishable level between 0.7 ms and 100 ms due to the vertical change in the aquifer properties. Furthermore, the electromagnetic variation generated by hydraulic connection between aquifers is greater than 30% within the range of 3/4 of the transmitting loop. Finally, a successful case history to map hydraulic connections between aquifers is conducted using a time-lapse TEM pre- and post- a pumping experiment. This simulation and field experiment shows that time-lapse TEM could characterize and monitor the groundwater migration more effectively than pump tests or hydrogeochemical methods alone.

Transient electromagnetic surveys for highresolution near-surface exploration: basics and case studies

First Break ◽  
2017 ◽  
Vol 35 (9) ◽  
Author(s):  
M.V. Sharlov ◽  
I.V. Buddo ◽  
N.V. Misyurkeeva ◽  
I.A. Shelokhov ◽  
Yu.A. Agafonov
Keyword(s):  
Case Studies ◽  
Near Surface ◽  
Transient Electromagnetic ◽  
Surface Exploration ◽  
Electromagnetic Surveys

A transient electromagnetic survey to define hydrogeology. A case history

1991 ◽  
Vol 27 (1-2) ◽  
pp. 43-54 ◽  
Author(s):  
Kendrick Taylor ◽  
Regina Bochicchio ◽  
Michael Widmer
Keyword(s):  
Case History ◽  
Transient Electromagnetic
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