FN Archimer Export Format
PT J
TI Characterization of gas‐bearing sediments in coastal environment using geophysical and geotechnical data
BT 
AF Dusart, Judith
   Tarits, Pascal
   Fabre, Maud
   Marsset, Bruno
   Jouet, Gwenael
   Ehrhold, Axel
   Riboulot, Vincent
   Baltzer, Agnes
AS 1:1,2;2:1,2;3:1;4:3;5:3;6:3;7:3;8:4;
FF 1:;2:;3:PDG-REM-GEOOCEAN-ALMA;4:PDG-REM-GEOOCEAN-ALMA;5:PDG-REM-GEOOCEAN-ASTRE;6:PDG-REM-GEOOCEAN-ASTRE;7:PDG-REM-GEOOCEAN-ALMA;8:;
C1 European Institute for Marine Studies (IUEM) ,Plouzané , France
   Mappem Geophysics SAS Saint‐Renan , France
   Ifremer, Plouzané , France
   University of Nantes, Lab Geolittomer Nantes 3, France
C2 UBO, FRANCE
   MAPPEM GEOPHYSICS SAS, FRANCE
   IFREMER, FRANCE
   UNIV NANTES, FRANCE
SI BREST
SE PDG-REM-GEOOCEAN-ALMA
   PDG-REM-GEOOCEAN-ASTRE
UM GEO-OCEAN
IN WOS Ifremer UMR
   WOS Cotutelle UMR
   copubli-france
   copubli-univ-france
IF 1.6
TC 1
UR https://archimer.ifremer.fr/doc/00783/89484/94998.pdf
LA English
DT Article
CR ESS_FLUTE PLATEAU
   SYPOCO 2018
BO Thalia
DE ;electrical resistivity tomography;modelling;porosity;seismics;shallow marine
AB Seismic investigation in marine gas-bearing sediments fails to get information below the acoustic mask created by free gas. To circumvent this problem, we combined collocated multichannel ultra-high resolution seismic imaging, marine electrical resistivity tomography (MERT) and core sampling to study the physical properties of gas-bearing sediments in the Bay of Concarneau (France). We obtained sections of compression (P-) wave velocitvalues where free gas was identified in seismic data. We tested a joint processing workflow combining the 1D inversion of the MERT data with the 2D P-wave velocity through a structural coupling between resistivity and velocity. We obtained a series of 2D resistivity models fitting the data whilst in agreement with. The resulting models showed the continuity of the geological units below the acoustic gas fronts which is associated with paleo-valley sediment infilling. We were able to demonstrate relationships between resistivity and velocity differing from superficial to deeper sediments. We established these relationships at the geophysical scale then compared the results to data from core sampliand porosity). We inferred the porosity distribution from the MERT data. At the core locations, we observed a good agreement between this geophysical scale porosity and the core data both within and outside the gas-bearing sediments. This agreement demonstrated that resistivity could be used as a proxy for porosity where no was available below gas caps. In these regions, the observed low resistivity showed a high porosity (60-70%) down to about 10–20 m in depth in contrast with the surrounding medium with porosity less than 55%. These results support the hypothesis that failures inside the paleo-valley sediment could control the gas migration 
PY 2022
PD OCT
SO Near Surface Geophysics
SN 1569-4445
PU Wiley
VL 20
IS 5
UT 000842631200001
BP 478
EP 493
DI 10.1002/nsg.12230
ID 89484
ER

EF