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Cross-borehole ERT : Sensitivity, model resolution, and field data quality

Madsen, L. M. ; Kühl, A. K. ; Levy, L. LU and Christiansen, A. V. (2021) 27th European Meeting of Environmental and Engineering Geophysics, Held at Near Surface Geoscience Conference and Exhibition 2021, NSG 2021 In 27th European Meeting of Environmental and Engineering Geophysics, Held at Near Surface Geoscience Conference and Exhibition 2021, NSG 2021 p.1-5
Abstract

Sensitivity, resolution, and data quality are important parameters to consider when designing an ERT cross-borehole survey. We present an open-source algorithm for computing 2D and 3D sensitivity patterns of any borehole setup and use this to compare single-borehole and different cross-borehole electrode configurations, which both show complex patterns. To study the resolution capability of an entire survey, the model resolution matrix is computed for a field dataset. The dataset is split into different electrode configurations and the model resolution matrices of the different configuration are compared. The results show that the sensitivity and resolution decreases very quickly away from the electrodes, especially for the... (More)

Sensitivity, resolution, and data quality are important parameters to consider when designing an ERT cross-borehole survey. We present an open-source algorithm for computing 2D and 3D sensitivity patterns of any borehole setup and use this to compare single-borehole and different cross-borehole electrode configurations, which both show complex patterns. To study the resolution capability of an entire survey, the model resolution matrix is computed for a field dataset. The dataset is split into different electrode configurations and the model resolution matrices of the different configuration are compared. The results show that the sensitivity and resolution decreases very quickly away from the electrodes, especially for the single-borehole configurations. In the studied field case, this means cross-borehole configurations are needed to correctly image the area between the boreholes, even though the cross-borehole data often are associated with a lower signal-to-noise ratio due to near-zero potential measurements and generally more outliers. The study concludes that in a production mode, where acquisition time and thus the number of possible data points are limited, the combination of electrode configurations must be carefully considered and a trade-off between resolution and data quality must be evaluated.

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author
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publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
host publication
27th European Meeting of Environmental and Engineering Geophysics, Held at Near Surface Geoscience Conference and Exhibition 2021, NSG 2021
series title
27th European Meeting of Environmental and Engineering Geophysics, Held at Near Surface Geoscience Conference and Exhibition 2021, NSG 2021
pages
1 - 5
publisher
Wiley-Blackwell
conference name
27th European Meeting of Environmental and Engineering Geophysics, Held at Near Surface Geoscience Conference and Exhibition 2021, NSG 2021
conference location
Bordeaux, Virtual, France
conference dates
2021-08-29 - 2021-09-02
external identifiers
  • scopus:85125280816
ISBN
9789462823860
DOI
10.3997/2214-4609.202120114
language
English
LU publication?
no
additional info
Funding Information: This work was supported by a research grant from VILLUM FONDEN (id: 37172) and by Innovation Fund Denmark through the project GIRem, Guided Injection Remediation, (id: 8055-00004B). The cross-borehole ERT data were collected with help from Region Hovedstaden in the Hvedemark project. Funding Information: This orw k asw supported by a research grant from LUM VLI ONF DEN i( d: 37172) and by nnoI atv ion uF nd Denmark through the project GRemI , Guided njI ection Reem iation, i( d: ERT data were colectl ed with help from Region Hovedstaden in the edemHv ark project. Publisher Copyright: © NSG 2021. All rights reserved.
id
1fa438d8-58da-4ee1-a496-c0e8a3243851
date added to LUP
2022-03-09 09:06:27
date last changed
2022-04-25 05:38:54
@inproceedings{1fa438d8-58da-4ee1-a496-c0e8a3243851,
  abstract     = {{<p>Sensitivity, resolution, and data quality are important parameters to consider when designing an ERT cross-borehole survey. We present an open-source algorithm for computing 2D and 3D sensitivity patterns of any borehole setup and use this to compare single-borehole and different cross-borehole electrode configurations, which both show complex patterns. To study the resolution capability of an entire survey, the model resolution matrix is computed for a field dataset. The dataset is split into different electrode configurations and the model resolution matrices of the different configuration are compared. The results show that the sensitivity and resolution decreases very quickly away from the electrodes, especially for the single-borehole configurations. In the studied field case, this means cross-borehole configurations are needed to correctly image the area between the boreholes, even though the cross-borehole data often are associated with a lower signal-to-noise ratio due to near-zero potential measurements and generally more outliers. The study concludes that in a production mode, where acquisition time and thus the number of possible data points are limited, the combination of electrode configurations must be carefully considered and a trade-off between resolution and data quality must be evaluated.</p>}},
  author       = {{Madsen, L. M. and Kühl, A. K. and Levy, L. and Christiansen, A. V.}},
  booktitle    = {{27th European Meeting of Environmental and Engineering Geophysics, Held at Near Surface Geoscience Conference and Exhibition 2021, NSG 2021}},
  isbn         = {{9789462823860}},
  language     = {{eng}},
  pages        = {{1--5}},
  publisher    = {{Wiley-Blackwell}},
  series       = {{27th European Meeting of Environmental and Engineering Geophysics, Held at Near Surface Geoscience Conference and Exhibition 2021, NSG 2021}},
  title        = {{Cross-borehole ERT : Sensitivity, model resolution, and field data quality}},
  url          = {{http://dx.doi.org/10.3997/2214-4609.202120114}},
  doi          = {{10.3997/2214-4609.202120114}},
  year         = {{2021}},
}