Physics – Geophysics
Scientific paper
Mar 2010
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010geoji.180.1095t&link_type=abstract
Geophysical Journal International, Volume 180, Issue 3, pp. 1095-1106.
Physics
Geophysics
5
Electrical Properties, Hydrogeophysics, Permeability And Porosity
Scientific paper
We investigated electrical and physical-chemical properties of six sandstone samples with contrasting mineralogical characteristics and with hydraulic conductivity varying in a wide range. The electrical data were obtained from time domain spectral induced polarization (IP) measurements.
We inverted the IP decays to relaxation time distributions, and then compared the modal relaxation times with the dominant pore throat diameters obtained from the Mercury Injection Capillary Pressure (MICP) data.
We found a positive logarithmic relationship between the relaxation time and the pore throat diameter. Also, we found the normalized chargeability (an integral IP parameter) to be positively correlated with the clay content. These two results suggest that the polarization of our sandstones is controlled by the pore throat distribution, and by the clay content.
The logarithmic relationship contradicts previous theories, and is not universal. Adopting an approach of Kruschwitz and her co-workers, we calculated the effective diffusivity from IP and MICP data, and we found the effective diffusivity values ranging from 2.9 × 10-13 to 1.6 × 10-10 m2s-1. High diffusivity values, typical of surface diffusion, were obtained for clean sandstones. Low diffusivity values were obtained for clayey sandstones, and they were one to two orders of magnitude lower than those characteristic of the surface diffusion.
We proposed two mechanisms to explain the `slow' diffusion: (1) the effect of surface tortuosity of pore throats filled with clay minerals and (2) the effect of pore geometry. These two effects represent an obstacle in assessing the pore throat diameter and hydraulic conductivity of sandstones with large specific surface and clay content on the basis of spectral IP measurements. However, we believe that the sandstones featuring `slow' diffusion can be discriminated based on the integral polarization parameters, and that the relaxation time remains a valuable parameter for assessing hydraulic properties of clean sandstones.
Boyd Austin
Ilyin Yuri
Seleznev Nikita
Tarasov Andrey
Titov Konstantin
No associations
LandOfFree
Relationships between induced polarization relaxation time and hydraulic properties of sandstone does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Relationships between induced polarization relaxation time and hydraulic properties of sandstone, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Relationships between induced polarization relaxation time and hydraulic properties of sandstone will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-880713