We have over 12,000 students, from over 100 countries, within one of the safest campuses in the UK


97% of Lancaster students go into work or further study within six months of graduating

Home > Research > Publications & Outputs > Electrical properties of partially saturated sa...
View graph of relations

« Back

Electrical properties of partially saturated sandstones.

Research output: Contribution to journalJournal article


<mark>Journal publication date</mark>17/08/2005
<mark>Journal</mark>Water Resources Research
<mark>Original language</mark>English


Electric and electromagnetic geophysical tools are suitable methods for investigating moisture content, transport, and storage properties of the subsoil with noninvasive surveys. Interpretation of field data is still based on empirical or semiempirical equations, which must be calibrated with complex, time-consuming laboratory measurements. In this paper we develop pore-scale models suitable for computing the effective electric conductivity and the effective permittivity of partially saturated porous media on the basis of simple structural parameters (grain size distribution and porosity). We compute the electrical conductivity with three approaches that model the conductivity of the shell of coating clay around solid grains of shaly sandstones using different assumptions. We compare the simulated results with experimental data from Sherwood Sandstone (UK) and discuss the effect of these assumptions on the effective conductivity. Simulations performed using a modeling approach that accounts for interaction between volume and surface conduction show an excellent agreement with experimental data. We also model the effective permittivity of the same porous medium at several saturation values and obtain a good match with laboratory measurements.