Comparison of interfacial partitioning tracer test and high‐resolution microtomography measurements of fluid‐fluid interfacial areas for an ideal porous medium

Abstract

Fluid-fluid interfacial area for porous-media systems can be measured with the aqueous-phase interfacial partitioning tracer test (IPTT) method or with high-resolution microtomography. The results of prior studies have shown that interfacial areas measured with the IPTT method are larger than values measured with microtomography. The observed disparity has been hypothesized to result from the impact of porous-medium surface roughness on film-associated interfacial area, wherein the influence of surface roughness is characterized to some extent by the IPTT method but not by microtomography due to resolution constraints. This hypothesis was tested by using the two methods to measure interfacial area between an organic immiscible liquid and water for an ideal glass-beads medium that has no measurable surface roughness. The tracer tests yielded a mean interfacial area of 2.8 (± 5 cm−1), while microtomography produced an interfacial area of 2.7 (± 2 cm−1). Maximum specific interfacial areas, equivalent to areas normalized by non-wetting fluid volume, were calculated and compared to measures of the specific solid surface area. The normalized interfacial areas were similar to the specific solid surface area calculated using the smooth-sphere assumption, and to the specific solid surface area measured using the N2/BET method. The results presented herein indicate that both the IPTT and microtomography methods provide robust characterization of fluid-fluid interfacial area, and that they are comparable absent the impact of surface roughness.

Interfacial Partitioning Tracer Test Measurements of Organic-Liquid/Water Interfacial Areas: Application to Soils and the Influence of Surface Roughness

“…The maximum interfacial areas obtained for the sands are significantly above the line. Also included in Figure 2 is a value obtained for a glass-bead medium that has no measurable surface roughness (19). In contrast to the sands and soils, the maximum interfacial area for the glass beads is similar to the specific solid surface area predicted using the smooth-sphere assumption.…”

“…Comparison of fluid-fluid interfacial areas for systems wherein fluid saturations differ is facilitated by use of such a system index. The results of prior research have shown that SA/VOL and A m values obtained under different conditions, such as drainage versus imbibition, are similar when based on total interfacial areas (18, 19). …”

Novel methods for measuring air–water interfacial area in unsaturated porous media

“…In addition, this tracer test can be conducted similarly to a saturated-flow experiment, which significantly reduces the required experiment time. This approach is similar to the standard IPTT met hod used to measure interfacial area between organic liquids and water (e.g., Saripalli et al, 1997; Cho and Annable, 2005; Dobson et al, 2006; Brusseau et al, 2008; Brusseau et al, 2010; Narter and Brusseau, 2010), but has to date not been used to measure air-water interfacial area. Experiments are conducted with the two novel approaches to measure air-water interfacial areas for two natural porous media.…”

On the challenges of measuring interfacial characteristics of three‐phase fluid flow with x‐ray microtomography

“…Synchrotron‐based computed microtomography (CMT) is a nondestructive method that generates three‐dimensional images at pore‐scale resolution, and it has been used fairly extensively to measure fluid properties in two‐phase flow systems, such as saturation and interfacial area (Culligan et al ., ; Brusseau et al ., ; Culligan et al ., ; Costanza‐Robinson et al ., ; Narter & Brusseau, ; Porter et al ., ) as well as residual nonwetting phase morphology (Al‐Raoush & Willson, ; Karpyn et al ., ; Landry et al ., ). It has been used to a much lesser extent to analyze three‐phase systems; studies have measured fluid volumes, oil blob morphologies and dimensions of spreading oil layers (Schnaar & Brusseau, ; Feali et al ., ; Iglauer et al ., ) and have evaluated the systems qualitatively (Alvarado et al ., ).…”

“…A number of groups have used CMT for measuring various features in two‐phase flow systems and have successfully implemented segmentation algorithms to accomplish this task (Culligan et al ., ; Brusseau et al ., ; Culligan et al ., ; Costanza‐Robinson et al ., ; Narter & Brusseau, ; Porter et al ., ; Armstrong et al ., ; Armstrong & Wildenschild, ). In addition; there have been a few publications dealing specifically with the segmentation issues associated with multi‐phase flow analyses (Iassonov et al ., ; Porter & Wildenschild, ; Kulkarni et al ., ).…”