Mercury cyclic porosimetry: Measuring pore-size distributions corrected for both pore-space accessivity and contact-angle hysteresis

We propose a set of simple formulae for interpreting mercury cyclic porosimetry measurements where multiple intrusion-extrusion cycles are carried out. By employing two parameters alpha is an element of [0, 1] and kappa is an element of [0, 1], our theory quantitatively breaks down any hysteresis observed in cyclic porosimetry data into contributions due to connectivity effects and contact-angle hysteresis, respectively. In particular, the parameter alpha, called pore-space accessivity, characterizes any serial connectivity between different-size pores. It has long been recognized that the standard method for determining the pore-size distribution (PSD) from mercury intrusion data based on the capillary bundle assumption overestimates the fraction of smaller pores; that corresponds to the alpha -> 1 limit of our model. In contrast, for materials with alpha < 1, our theory predicts a broadened PSD shifted toward larger radii, thus representing a simple way of rectifying PSDs for connectivity effects. The proposed model also establishes mercury cyclic porosimetry as a standard experimental procedure for measuring alpha, which can then be used in continuum models of porous media where connectivity effects play a significant role, such as in multiphase flow. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

The study proposes a set of simple formulas to interpret mercury cyclic porosimetry measurements, breaking down hysteresis in the data into connectivity effects and contact-angle hysteresis. The parameter alpha helps correct the overestimation of smaller pores due to connectivity effects, making mercury cyclic porosimetry a standard procedure for measuring connectivity in porous media.