%0 Journal Article %T Near-surface CO2 leak detection monitoring from downhole electrical resistivity at the CO2 Field Laboratory, Svelvik Ridge (Norway) %+ Géosciences Montpellier %+ Bureau de Recherches Géologiques et Minières (BRGM) (BRGM) %+ Schlumberger %A Denchik, Nataliya %A Pezard, P. %A Neyens, Denis %A Lofi, Johanna %A Gal, Frédérick %A Girard, Jean-François %A Levannier, Arnaud %< avec comité de lecture %@ 1750-5836 %J International Journal of Greenhouse Gas Control %I Elsevier %V 28 %P 275-282 %8 2014-01-01 %D 2014 %R 10.1016/j.ijggc.2014.06.033 %Z Sciences of the Universe [physics]/Earth SciencesJournal articles %X The objective of the CO 2 FieldLab project was to demonstrate that adequate monitoring methods can be deployed to document potential leaks of CO 2 from subsurface reservoirs. For this, a shallow injection experiment through permeable sediment was designed and conducted at Svelvik (Norway) in September 2011. The goal was to produce a CO 2 leak in order to assess the relative sensitivity of several geochemical and geophysical CO 2 monitoring tools. A total mass of 1.67tons of CO 2 was injected at a depth of 20m through a 45° inclined well over a 6 day period. Time-lapse induction logging and downhole resistivity monitoring from a permanent dipole–dipole array observatory prove to be very sensitive to the presence of CO 2 in the shallow subsurface after the start of injection. Electrical resistivity response correlates with progressive CO 2 dissolution in groundwater, with resistivity and pH values decreasing due to the increase of bicarbonate and dissolved species. The CO 2 plume is channelled by enhanced permeability layers, with updip migration of the gas plume to the North. Other processes responsible for resistivity changes were fresh/salt water mixing, tidal effects and rainfall. %G English %L hal-01314405 %U https://brgm.hal.science/hal-01314405 %~ INSU %~ BRGM %~ UNIV-AG %~ CNRS %~ GM %~ AGROPOLIS %~ B3ESTE %~ UNIV-MONTPELLIER %~ BRGM-DO %~ UM-2015-2021 %~ TEST3-HALCNRS