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@ARTICLE{Weller:20815,
author = {Weller, A. and Breede, K. and Slater, L. and Nordsiek, S.},
title = {{E}ffect of changing water salinity on complex conductivity
spectra of sandstones},
journal = {Geophysics},
volume = {76},
issn = {0016-8033},
address = {Tulsa, Okla.},
publisher = {SEG},
reportid = {PreJuSER-20815},
pages = {F315 - F327},
year = {2011},
note = {Record converted from VDB: 12.11.2012},
abstract = {We analyzed the influence of pore fluid composition on the
complex electrical conductivity of three sandstones with
differing porosity and permeability. The fluid electrical
conductivity (sigma(w)) of sodium and calcium chloride
solutions was gradually increased from 25 mS/m to 2300 mS/m.
The expected linear relation between sigma(w) and the real
component of electrical conductivity (sigma') of the
saturated samples was observed. The imaginary component
(sigma '') exhibits a steeper increase at lower salinities
that flattens at higher salinities. For a glauconitic
sandstone and a high porosity Bunter sandstone, sigma ''
approaches an asymptotic value at high salinities. Sodium
cations result in larger values of sigma '' than calcium
cations in solutions of equal concentration. Debye
decomposition was used to determine normalized chargeability
(m(n)) and average relaxation time (tau) from spectral data.
The behavior of sigma '' is comparable to m(n) as both
parameters measure the polarizability. At lower salinity,
the relation between m(n) and sigma(w) approximates a power
law with an exponent of similar to 0.5. The average
relaxation time shows only a weak dependence on sigma(w).
The normalized chargeability of sandstone samples can be
described by the product of the pore space related internal
surface and a quantity characterizing the polarizability of
the mineral-fluid interface that depends on fluid chemistry.
We introduce a new parameter, the specific polarizability,
describing this dependence. We propose relations between
polarizability and fluid chemistry that could be used to
estimate pore space internal surface across samples of
varying sigma(w). We observe a consistent maximum
polarizability for quartz dominated siliceous material.},
keywords = {J (WoSType)},
cin = {IBG-3},
ddc = {550},
cid = {I:(DE-Juel1)IBG-3-20101118},
pnm = {Terrestrische Umwelt},
pid = {G:(DE-Juel1)FUEK407},
shelfmark = {Geochemistry $\&$ Geophysics},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000297946200014},
doi = {10.1190/geo2011-0072.1},
url = {https://juser.fz-juelich.de/record/20815},
}