Cross-Borehole ERT: Sensitivity, Model Resolution, and Field Data Quality

Line Meldgaard Madsen; Anders Kristian Kühl; Léa Lévy; Anders Vest Christiansen

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 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.

Originalsprog	Engelsk
Publikationsdato	2021
Antal sider	5
Status	Udgivet - 2021
Begivenhed	EAGE Near Surface Geoscience 2021 - Bordeaux, Frankrig Varighed: 30 aug. 2021 → 1 sep. 2021 https://eage.eventsair.com/nsg2021/

Konference

Konference	EAGE Near Surface Geoscience 2021
Land/Område	Frankrig
By	Bordeaux
Periode	30/08/2021 → 01/09/2021
Internetadresse	https://eage.eventsair.com/nsg2021/

Adgang til dokumentet

https://www.earthdoc.org/content/papers/10.3997/2214-4609.202120114

Tjek tilgængelighed hos det Kgl. Bibliotek

Andre filer og links

Link to publication in Scopus

Villum International Postdoc: Fusion of hydrological and geophysical modelling for a description of surface- and groundwater dynamics in a changing climate
Meldgaard Madsen, L. (PI)
01/04/2021 → 31/01/2024
Projekter: Projekt › Forskning
GIRem: Guided Injection Remediation (GIRem )
Christiansen, A. V. (PI), Larsen, J. J. (PI), Maurya, P. K. (Deltager), Liu, L. (Deltager), Domenzain Gonzalez, D. (Deltager), Kühl, A. K. (Deltager), Meldgaard Madsen, L. (Deltager), Barfod, A. (Deltager), Nielsen, A. N. (Deltager), Auken, E. (Deltager) & Dalsgaard, K. E. (Deltager)
01/07/2018 → 31/12/2022
Projekter: Projekt › Forskning

Citationsformater

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title = "Cross-Borehole ERT: Sensitivity, Model Resolution, and Field Data Quality",

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 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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AU - Meldgaard Madsen, Line

AU - Kühl, Anders Kristian

AU - Lévy, Léa

AU - Christiansen, Anders Vest

PY - 2021

Y1 - 2021

N2 - 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.

AB - 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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