Abstract
The low-frequency dielectric spectroscopy of granular material, where the porosity is representative for sands and sandstones, is until now always modeled using theories based on the work of Schwartz (1962). The theory for the low-frequency dielectric spectroscopy of suspensions, on the other hand, has been developed much further over the last decades both numerically and analytically.In this article new analytical expressions for the complex conductivity of granular material, such as sands and sandstones in an electrolyte solution, are presented. These expressions have been derived using the theories developed for suspensions. We show that the new expressions enable to predict the measured complex conductivity of various granular material, such as packed glass beads, sands and sandstones. Because of the typical grain size of sand and sandstone particles, for any ionic strength the double layer is much thinner that the particle size. Contrary to existing theories for granular materials, the expressions we derived are valid for any ionic strength and no adjustable parameters are required.The grains are represented by monodispersed charged spheres. We also discuss how the expressions can be adapted in the case the particles are not spherical and the grains are polydisperse.
Highlights
DC and AC conductivity measurements are usually performed to predict the reservoir properties of granular materials and porous rocks [1,2,3]
We show that the new expressions enable to predict the measured complex conductivity of various granular material, such as packed glass beads, sands and sandstones
Contrary to existing theories for granular materials, the expressions we derived are valid for any ionic strength and no adjustable parameters are required
Summary
DC and AC conductivity measurements are usually performed to predict the reservoir properties of granular materials and porous rocks [1,2,3] These properties are in particular: porosity, surface charge, grain or pore sizes and fluid saturation. In this article new analytical expressions for the complex conductivity of granular material, such as sands and sandstones in an electrolyte solution, are presented. (9) for the Maxwell–Wagner formalism and Eq (16) for the Bruggeman formalism These expressions are derived using an analytical theory for the dielectric response of a colloidal particle in an applied electric field [21] that reproduces the full numerical solutions of the electrokinetic set of equations within a few percent. We discuss how the expressions can be adapted in the case the particles are not spherical and the grains are polydisperse
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Colloids and Surfaces A: Physicochemical and Engineering Aspects
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
