Experimental compaction of clays: relationship between permeability and petrophysical properties in mudstones

Pore Size and Permeability of Experimentally Compacted Smectire and Kaolinite Clay. Permeability and Elastic Moduli

“…In the studied interval it ranges between 0.2 for the lowest porosity to 0.26 for the highest porosity (Mortensen et al 1998). Data points with white dots are not measured but estimated by Mondol et al (2008).…”

“…We find that tests with kaolinite plots on a trend very close to the measured BET, whereas smectitic tests fall on higher BET than the measured and on a trend of increasing BET with declining porosity. It should be borne in mind that the permeabilities for smectitic tests range from 10 -18 m 2 to 10 -22 m 2 (1 D -0.1 nD) and are difficult to measure, some of the data reported by Mondol et al (2008) are for this reason estimated from trends. The possibility remains that in this low permeability range, permeability modeled from porosity and BET is more reliable than measured data.…”

“…This is seen also in intervals where clay and shale samples easily disintegrate in water, which would indicate that the porosity reduction is merely a consequence of mechanical compaction. Mondol et al (2007Mondol et al ( , 2008 studied this phenomenon by laboratory experiments involving compaction of dry or sea-water saturated smectite and kaolonite powder. During these tests, velocity of elastic compressional waves and of elastic shear waves was measured; the volume of expelled water was monitored, and porosity () as well as bulk density, , could be calculated.…”

Effect of diagenesis on pore pressures in fine-grained rocks in the Egersund Basin, Central North Sea

“…Fine-grained, clay-rich sediments can maintain high amounts of bound water due to their large specific surface area and high cation exchange capacity (Henry, 1997;Conin et al, 2011). On the other hand, these sediments have rela tively low permea bilities which makes it even more difficult to expel the pore fluid out of the pore space during compaction (Mondol et al, 2008a). Thus, mudstones and shales are prone to show overpressure during mechanical compaction.…”

Pore Radius and Permeability Prediction from Sonic Velocity

“…A critical literature review by Mondol et al, (2008) on available permeability models, concluded that none of the existing models is ideal and all need to be calibrated and validated through a much larger permeability database of well-characterized mudstones. His results on smectite and kaolinite aggregates suggest that the permeability of smectitic clays may be up to five orders of magnitude lower than that of kaolinitic clays with the same porosity, density, velocity or rock mechanical properties.…”