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Measuring time-domain spectral induced polarization in the on-time: decreasing acquisition time and increasing signal-to-noise ratio

Olsson, Per-Ivar LU ; Dahlin, Torleif LU ; Fiandaca, Gianluca and Auken, Esben (2015) In Journal of Applied Geophysics 123. p.316-321
Abstract
Combined resistivity and time-domain direct current induced polarization (DCIP) measurements are traditionally carried out with a 50\% duty cycle current waveform, taking the resistivity measurements during the on-time and the IP measurements during the off-time. One drawback with this method is that only half of the acquisition time is available for resistivity and IP measurements, respectively. In this paper, this limitation is solved by using a current injection with 100\% duty cycle and also taking the IP measurements in the on-time. With numerical modelling of current waveforms with 50\% and 100\% duty cycles we show that the waveforms have comparable sensitivity for the spectral Cole–Cole parameters and that signal level is increased... (More)
Combined resistivity and time-domain direct current induced polarization (DCIP) measurements are traditionally carried out with a 50\% duty cycle current waveform, taking the resistivity measurements during the on-time and the IP measurements during the off-time. One drawback with this method is that only half of the acquisition time is available for resistivity and IP measurements, respectively. In this paper, this limitation is solved by using a current injection with 100\% duty cycle and also taking the IP measurements in the on-time. With numerical modelling of current waveforms with 50\% and 100\% duty cycles we show that the waveforms have comparable sensitivity for the spectral Cole–Cole parameters and that signal level is increased up to a factor of 2 if the 100\% duty cycle waveform is used. The inversion of field data acquired with both waveforms confirms the modelling results and shows that it is possible to retrieve similar inversion models with either of the waveforms when inverting for the spectral Cole–Cole parameters with the waveform of the injected current included in the forward computations. Consequently, our results show that on-time measurements of IP can reduce the acquisition time by up to 50\% and increase the signal-to-noise ratio by up to 100\% almost without information loss. Our findings can contribute and have a large impact for DCIP surveys in general and especially for surveys where time and reliable data quality are important factors. Specifically, the findings are of value for DCIP surveys conducted in urban areas where anthropogenic noise is an issue and the heterogeneous subsurface demands time-consuming 3D acquisitions. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Cole–Cole, Duty cycle, Induced polarization, SNR, Signal-to-noise ratio, Spectral, Waveform
in
Journal of Applied Geophysics
volume
123
pages
316 - 321
publisher
Elsevier
external identifiers
  • wos:000366073400031
  • scopus:84947866498
ISSN
0926-9851
DOI
10.1016/j.jappgeo.2015.08.009
language
English
LU publication?
yes
id
31d06abf-6ac5-4d52-8800-63ebebeb0a65 (old id 7866832)
date added to LUP
2015-09-29 13:57:29
date last changed
2017-11-12 03:47:30
@article{31d06abf-6ac5-4d52-8800-63ebebeb0a65,
  abstract     = {Combined resistivity and time-domain direct current induced polarization (DCIP) measurements are traditionally carried out with a 50\% duty cycle current waveform, taking the resistivity measurements during the on-time and the IP measurements during the off-time. One drawback with this method is that only half of the acquisition time is available for resistivity and IP measurements, respectively. In this paper, this limitation is solved by using a current injection with 100\% duty cycle and also taking the IP measurements in the on-time. With numerical modelling of current waveforms with 50\% and 100\% duty cycles we show that the waveforms have comparable sensitivity for the spectral Cole–Cole parameters and that signal level is increased up to a factor of 2 if the 100\% duty cycle waveform is used. The inversion of field data acquired with both waveforms confirms the modelling results and shows that it is possible to retrieve similar inversion models with either of the waveforms when inverting for the spectral Cole–Cole parameters with the waveform of the injected current included in the forward computations. Consequently, our results show that on-time measurements of IP can reduce the acquisition time by up to 50\% and increase the signal-to-noise ratio by up to 100\% almost without information loss. Our findings can contribute and have a large impact for DCIP surveys in general and especially for surveys where time and reliable data quality are important factors. Specifically, the findings are of value for DCIP surveys conducted in urban areas where anthropogenic noise is an issue and the heterogeneous subsurface demands time-consuming 3D acquisitions.},
  author       = {Olsson, Per-Ivar and Dahlin, Torleif and Fiandaca, Gianluca and Auken, Esben},
  issn         = {0926-9851},
  keyword      = {Cole–Cole,Duty cycle,Induced polarization,SNR,Signal-to-noise ratio,Spectral,Waveform},
  language     = {eng},
  pages        = {316--321},
  publisher    = {Elsevier},
  series       = {Journal of Applied Geophysics},
  title        = {Measuring time-domain spectral induced polarization in the on-time: decreasing acquisition time and increasing signal-to-noise ratio},
  url          = {http://dx.doi.org/10.1016/j.jappgeo.2015.08.009},
  volume       = {123},
  year         = {2015},
}