TY - GEN
T1 - Using electrical resistivity tomography and self-potential methods for wells implementations in fractured limestones
AU - Robert, T.
AU - Dassargues, A.
AU - Brouyère, S.
AU - Kaufmann, O.
AU - Hallet, V.
AU - Nguyen, F.
PY - 2009
Y1 - 2009
N2 - Electrical resistivity tomography (ERT) and self-potential (SP) investigations were conducted in fractured limestones in Belgium. The aim of this study was to find suitable positions for high yield water wells. Large ERT profiles (640 meters) allowed us to image the resistivity distribution of the first 60 meters of the subsurface and to detect and characterize (in terms of direction, width and depth) fractured zones expected to be less resistive. Data errors, DOI indexes and sensitivity models were analysed in order to calculate the depth of investigation of ERT and to avoid the misinterpretation of the resulting images. Self-potential measurements were performed along electrical profiles to narrow the possible locations given by the electrical images. Some negative anomalies possibly related to preferential flow were detected. Ground truth geological data as well as pumping tests information gave us a way to assess the contribution of geophysics to a drilling programme. Wells implemented in low resistivity zones associated with SP anomalies have very high yields. Inversely, wells drilled in resistive zones or outside SP anomalies have poorer capacities. An apparent coupling coefficient between SP signals and differences in hydraulic heads was also estimated in order to image the water table.
AB - Electrical resistivity tomography (ERT) and self-potential (SP) investigations were conducted in fractured limestones in Belgium. The aim of this study was to find suitable positions for high yield water wells. Large ERT profiles (640 meters) allowed us to image the resistivity distribution of the first 60 meters of the subsurface and to detect and characterize (in terms of direction, width and depth) fractured zones expected to be less resistive. Data errors, DOI indexes and sensitivity models were analysed in order to calculate the depth of investigation of ERT and to avoid the misinterpretation of the resulting images. Self-potential measurements were performed along electrical profiles to narrow the possible locations given by the electrical images. Some negative anomalies possibly related to preferential flow were detected. Ground truth geological data as well as pumping tests information gave us a way to assess the contribution of geophysics to a drilling programme. Wells implemented in low resistivity zones associated with SP anomalies have very high yields. Inversely, wells drilled in resistive zones or outside SP anomalies have poorer capacities. An apparent coupling coefficient between SP signals and differences in hydraulic heads was also estimated in order to image the water table.
UR - http://www.scopus.com/inward/record.url?scp=85085776785&partnerID=8YFLogxK
U2 - 10.3997/2214-4609.20147017
DO - 10.3997/2214-4609.20147017
M3 - Conference contribution
AN - SCOPUS:85085776785
SN - 9073781728
SN - 9789073781726
T3 - Near Surface 2009 - 15th European Meeting of Environmental and Engineering Geophysics
BT - Near Surface 2009 - 15th European Meeting of Environmental and Engineering Geophysics
PB - European Association of Geoscientists and Engineers, EAGE
T2 - 15th European Meeting of Environmental and Engineering Geophysics of the Near Surface Geoscience Division of EAGE, Near Surface 2009
Y2 - 7 September 2009 through 9 September 2009
ER -