TY - GEN
T1 - An algorithm for 3D modelling of direct current resistivity and full-response time-domain induced polarization data
AU - Madsen, L.M.
AU - Fiandaca, G.
AU - Auken, E.
N1 - Publisher Copyright:
© 2021 J and N Group, Ltd.. All rights reserved.
PY - 2021
Y1 - 2021
N2 - We present a flexible algorithm for modelling of 3D direct current (DC) resistivity and time-domain induced polarization (IP) data. A structured model mesh allows easy implantation of constrains, whereas the finite-element forward algorithm is based on unstructured tetrahedral meshes and therefore handles both topography, arbitrary shaped boundaries and local refinement. This, together with modelling of the secondary potential field for singularity removal around the sources, ensures high accuracy. Electrodes may be placed on the boundaries or arbitrarily in the subsurface thus allowing both surface and cross-borehole applications. The forward response is computed in frequency-domain and then transformed to time-domain using the Hankel Transform, taking into account the current waveform and system filters for a quantitative IP modelling of either full-decay IP responses or integral chargeability allowing the IP phenomenon to be parameterised using any IP parameterization. An accuracy test of the forward response shows the advantages of the singularity removal (computing primary and secondary potential fields separately) as it decreases the relative deviation to the analytic solution significantly compared to computing the total field.
AB - We present a flexible algorithm for modelling of 3D direct current (DC) resistivity and time-domain induced polarization (IP) data. A structured model mesh allows easy implantation of constrains, whereas the finite-element forward algorithm is based on unstructured tetrahedral meshes and therefore handles both topography, arbitrary shaped boundaries and local refinement. This, together with modelling of the secondary potential field for singularity removal around the sources, ensures high accuracy. Electrodes may be placed on the boundaries or arbitrarily in the subsurface thus allowing both surface and cross-borehole applications. The forward response is computed in frequency-domain and then transformed to time-domain using the Hankel Transform, taking into account the current waveform and system filters for a quantitative IP modelling of either full-decay IP responses or integral chargeability allowing the IP phenomenon to be parameterised using any IP parameterization. An accuracy test of the forward response shows the advantages of the singularity removal (computing primary and secondary potential fields separately) as it decreases the relative deviation to the analytic solution significantly compared to computing the total field.
UR - http://www.scopus.com/inward/record.url?scp=85106170991&partnerID=8YFLogxK
U2 - 10.4133/sageep.33-025
DO - 10.4133/sageep.33-025
M3 - Conference article in proceedings
AN - SCOPUS:85106170991
T3 - Proceedings of the Symposium on the Application of Geophyics to Engineering and Environmental Problems, SAGEEP
SP - 49
EP - 53
BT - 33rd Symposium on the Application of Geophysics to Engineering and Environmental Problems, SAGEEP 2021
PB - Environmental and Engineering Geophysical Society
T2 - 33rd Symposium on the Application of Geophysics to Engineering and Environmental Problems, SAGEEP 2021
Y2 - 14 March 2021 through 19 March 2021
ER -