An experimental study on the rate and mechanism of capillary rise in sandstone

Abstract

The Lucas-Washburn equation is a fundamental expression used to describe capillary rise in geologic media on the basis of pore radius, liquid viscosity, surface tension, contact angle, and time. It is known that a radius value significantly smaller than the main pore radius must be used in the equation in order for the predictions to fit the experimentally measured values. To evaluate this gap between theoretical predictions and experimental data, we conducted several capillary rise experiments using Berea sandstone. First, to investigate conditions in which pores of any size are available for capillary rise, an experiment was conducted using a dried core. Next, to adjust the size distribution of pore water before the capillary rise, gas pressure was applied to a water-saturated core and water was expelled from pores of r > 10 μm; then, capillary rise was initiated. Under this condition, capillary rise occurred only in the pores of r > 10 μm. The same experiment was conducted for r = 3, 1, and 0.36 μm. When narrower pores were made available for capillary rise, the overall rate of rise decreased and approached the rate observed when the sample was dry initially. This observation suggests that the capillary rise in narrow pores plays a significant role in the overall rate. Based on these results, we propose a conceptual capillary rise model that considers differing radii in branched pores and provide an example of a quantitative description of capillary rise.

Black manganese-rich crusts on a Gothic cathedral

“…Thus, to obtain enough Mn to form a crust of 3.4% MnO (J12SC) from a sandstone with < 0.015% MnO, transport of all available Mn present in the sandstone from a depth of at least 5 cm to the surface would be necessary. This depth is indeed in the range where capillary rise can occur in porous sandstones (Tsunazawa et al, 2016). However, no Mn-lined fissures are observable in cross sections and the crusts seem to be continuous layers and not predominantly abundant close to pore systems or intruding the rock surface similar to weathering crusts (Fig.…”

Hygric properties of porous building materials (III): Impact factors and data processing methods of the capillary absorption test

“…To reduce evaporation, the lateral and top sides of the sample are often sealed with non-permeable materials. In general, there are two sealing methods: either to cover these sides with a(n adhesive) film [11] or to coat them with paint or resin [22]. In the ASTM C1585 standard [28], it is clearly stated that both methods are acceptable.…”

Characterization of SiC ceramics with complex porosity by capillary infiltration: Part A - Filling by hexadecane at 20 °C

“…Liquids rising in porous media plays a determinant role in numerous fields such as geology, concrete, oil recovery, catalysis, textile, paper industry, food processing, biotechnology, and in the production of structural materials by melt-infiltration [1][2][3][4][5][6][7][8][9]. Structural composites (CMC and MMC) are advanced materials widely used for aerospace, automotive, defense, and general engineering applications [10].…”