Kv. Titov et Va. Tarasov, Time constants of induced polarization in water-saturated sands: Theory and experiments, GEOL GEOFIZ, 42(6), 2001, pp. 988-995
The paper presents a theoretical description of Induced polarization decay
In Ion-conductive rocks, which develops the steady-state model of Friedrich
sberg-Sidorova based on the diffusion nature of Induced polarization. Grain
contacts and pore space filled with interstitial liquid are regarded as na
rrowing and broadening current conduits that are characterized by different
transport numbers. An analytical solution of the unsteady diffusion equati
on yielded an expression describing time constants of Induced polarization
for a model In which wide pores are much longer than the narrow ones. Exper
imental transient characteristics obtained for sands with different average
grain sizes are consistent with the suggested theory.
According to theoretical and experimental results, the time constant of ind
uced polarization decay for pure sand is proportional to the square of its
average grain size.