Preferential pathways inversion from cross-borehole electrical data
- Léa Lelimouzin,
- Cédric Champollion,
- Léa Lévy,
- Delphine Roubinet
Cédric Champollion
Geosciences Montpellier - Montpellier Université
Author ProfileDelphine Roubinet
CNRS UMR5243, University of Montpellier
Author ProfileAbstract
Identification of preferential flow-paths, such as fractures, is
required for various issues in geosciences. When chemicals are injected
into the subsurface, monitoring the resulting structural and chemical
changes remains a challenge. The ability of geophysical tomography to
tackle this problem is not fully explored due to the lack of numerical
methods suitable for modelling narrow structures. We explore how
discrete representation of preferential flow-paths provides innovative
ways to invert electrical resistivity data collected during reagent
injection at a contaminated site. The dataset is inverted with a scheme
where a new fracture is added at every iteration. This allows
identifying newly-created narrow conductive structures from the field
data collected before and after injection. Fracture location remains
overall consistent despite using different starting points for the
fracture search. A priori constraints on fracture length improve
convergence. These results show the potential of discrete inversion for
identifying narrow structures from electrical resistivity monitoring.11 Jul 2024Submitted to ESS Open Archive 11 Jul 2024Published in ESS Open Archive