1887
  1. Home
  2. A-Z Publications
  3. Geophysical Prospecting
  4. Volume 66, Issue 1
  5. Article
Volume 66 Number 1
  • E-ISSN: 1365-2478

Abstract

ABSTRACT

Measurement of the electric field data due to an inductive loop source in a controlled source electromagnetic survey is not common, because electric field data, usually involving grounded electrodes, are expensive to acquire and difficult to interpret. With the recently developed capability of versatile three‐dimensional inversion, we revisit the idea of measuring electric field in a large ground loop survey for mineral exploration. The three‐dimensional modelling and inversion approach helps us quantitatively understand the detectability and recoverability of the proposed survey configuration. Our detectability study using forward modelling shows that the relative anomaly (percentage difference) in electric field does not decay with a lower induction number, but the conventional magnetic field data () does. Our recoverability study examines how much and what kind of information can be extracted from electric field data for the reconstruction of a three‐dimensional model. Synthetic inversions show the following observations. (i) Electric field data are good at locating lateral discontinuity, whereas has better depth resolution. (ii) Electric field is less sensitive to the background conductivity and, thus, is prone to misinterpretation because of a bad initial model in inversion. We recommend warm‐starting the electric field inversion with an initial model from a separate inversion. (iii) Electric field data may be severely contaminated by near‐surface heterogeneity, but an inversion can recover the deep target concealed by the geologic noise. (iv) Even one line of single‐component electric field data can greatly improve the horizontal resolution in a inversion. Finally, we investigate a field dataset of both electric field and measurements at a uranium deposit. The field example confirms that the electric field and magnetic field data contain independent information that is crucial in the accurate recovery of subsurface conductivity. Our synthetic and field examples demonstrate the benefit of acquiring electric field data along with magnetic field data in an inductive source survey.

© 2018 European Association of Geoscientists & Engineers © 2017 European Association of Geoscientists & Engineers
Loading

Article metrics loading...

/content/journals/10.1111/1365-2478.12529
2017-05-25
2024-04-20

  • From This Site

    /content/journals/10.1111/1365-2478.12529
    dcterms_title,dcterms_subject,pub_keyword
    -contentType:Journal -contentType:Contributor -contentType:Concept -contentType:Institution
    10
    5
Loading full text...

Full text loading...

References

  1. AmestoyP.R., DuffI.S. and L'ExcellentJ.‐Y.2000. Multifrontal parallel distributed symmetric and unsymmetric solvers. Computer Methods in Applied Mechanics and Engineering184, 501–520.
     [Google Scholar]
  2. HaberE., AscherU., AruliahD. and OldenburgD.2000. Fast simulation of 3D electromagnetic problems using potentials. Journal of Computational Physics163, 150–171.
     [Google Scholar]
  3. HibbsA., PetrovT., PendletonJ., MilbergerS., EiskampG. and WilsonG.A.2012. New electromagnetic sensors for magnetotelluric and induced polarization geophysical surveys. SEG Technical Program, Expanded Abstracts, 1–5.
  4. JonesA.G.1988. Static shift of magnetotelluric data and its removal in a sedimentary basin environment. Geophysics53, 967–978.
     [Google Scholar]
  5. MacnaeJ.C.1980. Geophysical prospecting with electric fields from an inductive EM source . PhD thesis, University of Toronto, Canada.
  6. MacnaeJ. and IrvineR.1988. Inductive source resistivity: a tool for outlining silicification in gold exploration. Exploration Geophysics19, 471–480.
     [Google Scholar]
  7. MacnaeJ., McGowanP. and LamontagneY.1989. Resistivity mapping using inductive sources. Exploration Geophysics20, 47–50.
     [Google Scholar]
  8. MarsalaA. and HibbsA.2015. Sensor for measuring the electromagnetic fields on land and underwater. (WO Patent App. PCT/US2014/041,200).
  9. NimeckG. and KochR.2008. A progressive geophysical exploration strategy at the Shea Creek uranium deposit. The Leading Edge27, 52–63.
     [Google Scholar]
  10. OldenburgD.W., HaberE. and ShekhtmanR.2013. Three‐dimensional inversion of multisource time domain electromagnetic data. Geophysics78, E47–E57.
     [Google Scholar]
  11. RhysD., EriksS. and van der MeerL.2010. Geology of the Shea Creek uranium deposits: an expanding uranium district in the Western Athabasca Basin. Presented at the Saskatchewan Geological Survey Open House.
  12. SternbergB.K., WashburneJ.C. and PellerinL.1988. Correction for the static shift in magnetotellurics using transient electromagnetic soundings. Geophysics53, 1459–1468.
     [Google Scholar]
  13. StrackK.‐M.1992. Exploration With Deep Transient Electromagnetics, Vol. 373. Amsterdam, Netherlands: Elsevier.
     [Google Scholar]
  14. TikhonovA. and ArseninV.Y.1977. Methods for Solving Ill‐posed Problems. John Wiley and Sons, Inc.
     [Google Scholar]
  15. Torres‐VerdinC. and BostickJrF.X.1992. Principles of spatial surface electric field filtering in magnetotellurics: electromagnetic array profiling (EMAP). Geophysics57, 603–622.
     [Google Scholar]
  16. WestG., MacnaeJ.C. and LamontagneY.1984. A time‐domain EM system measuring the step response of the ground. Geophysics49, 1010–1026.
     [Google Scholar]
http://instance.metastore.ingenta.com/content/journals/10.1111/1365-2478.12529
Loading
Electric field data in inductive source electromagnetic surveys
Geophysical Prospecting 66, 207 (2018); https://doi.org/10.1111/1365-2478.12529
/content/journals/10.1111/1365-2478.12529
/content/journals/10.1111/1365-2478.12529
Loading

Data & Media loading...

  • Article Type: Research Article
Keyword(s): Electrical field; Electromagnetics; Inversion

Most Cited This Month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error