Micro-tomographic analyses of specific interfacial area inside unconsolidated porous media with differing particle characteristics from microscopic to macroscopic scale

Abstract Hypothesis In capillary trapping in an unconsolidated porous medium, the interphase area is influenced by the distribution of the trapped phase clusters. These attributes, in turn, are affected by particle characteristics, indicating that the interphase area is affected by the particle characteristics. Experiments A micro-tomography technique was used to observe capillary trapping of a nitrogen-water system. The effect of particle characteristics on micro- to macroscopic properties was measured, respectively: pore size distribution (PSD) and porosity, bubble size distribution (BSD) and saturation, and bubble surface area and specific interfacial area. Capillary trapping experiments were carried out for media consisting of different particle shapes, range of sizes, and degrees of uniformity. Findings Particle characteristics govern not only the PSD but also the pore shape. Then, the PSD and pore shape govern the BSD and bubble surface area, thus, affecting the specific interfacial area. The specific interfacial area of highly angular particles differs from that of highly spherical particles and natural sands. On the basis of these findings, a statistical model of PSD and a bubble morphology model are developed. Comparisons of specific interfacial area with uniform bubble distribution and thermodynamic filling assumption models show that those assumptions predict interfacial area less accurately.