Hydraulic Permeability Prediction from Induced Polarization Data at Field Scale
G. Fiandaca, P.K. Maurya, N. Balbarini, A. Hördt, I. Møller, V. Rønde, N. Foged, P.L. Bjerg, A.V. Christiansen and E. Auken
Event name: 24th European Meeting of Environmental and Engineering Geophysics
Session: Hydrogeophysics I
Publication date: 09 September 2018
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In this study we present the prediction of hydraulic permeability (k) from time-domain spectral induced polarization (IP) data, measured in boreholes and along 2D surface profiles. The borehole data were collected with the El-log technique, which provides undisturbed “while drilling” measurements of the direct current (DC) resistivity, time-domain IP data and gamma radiation. Data were measured on unconsolidated formations at a landfill site in South Denmark, in three boreholes and along 16 2D profiles. DC and full-decay IP data were inverted in terms of the BIC re-parameterization of the Cole-Cole model, which present smaller parameter correlations and disentangles bulk and surface conduction. Permeability values were computed from bulk conductivity and the maximum imaginary conductivity, using the empirically-derived formulae presented in a recent study without any calibration. The IP-derived k estimates were compared to those estimated using grain size analysis and slug tests, for a total of 157 comparisons. A good correlation, on average within one decade, was found between the k estimates over four orders of magnitude, with similar depth-trends. In conclusion, IP can be reliably used for estimating hydraulic permeability on unconsolidated formations at the field scale, using the relations found in the laboratory without any further calibration.