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Category Text Publication
Reference Category Journals
DOI 10.1007/s11242-016-0641-y
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Title (Primary) Impact of surface roughness on capillary trapping using 2D-micromodel visualization experiments
Author Geistlinger, H.; Ataei-Dadavi, I.; Vogel, H.-J.
Journal Transport in Porous Media
Year 2016
Department BOPHY
Volume 112
Issue 1
Page From 207
Page To 227
Language englisch
Keywords 2D-micromodel with rough surface; Precursor thin-film flow; Snap-off trapping; Universal power law; Ordinary bond percolation
UFZ wide themes RU1
Abstract According to experimental observations, capillary trapping is strongly dependent on the roughness of the pore–solid interface. We performed imbibition experiments in the range of capillary numbers (Ca) from 10−6 to 5×10−5 using 2D-micromodels, which exhibit a rough surface. The microstructure comprises a double-porosity structure with pronounced macropores. The dynamics of precursor thin-film flow and its importance for capillary trapping are studied. The experimental data for thin-film flow advancement show a square-root time dependence. Based on the experimental data, we conducted inverse modeling to investigate the influence of surface roughness on the dynamic contact angle of precursor thin-film flow. Our experimental results show that trapped gas saturation decreases logarithmically with an increasing capillary number. Cluster analysis shows that the morphology and number of trapped clusters change with capillary number. We demonstrate that capillary trapping shows significant differences for vertical flow and horizontal flow. We found that our experimental results agree with theoretical results of percolation theory for Ca=10−6: (i) a universal power-like cluster size distribution, (ii) the linear surface–volume relationship of trapped clusters, and (iii) the existence of the cutoff correlation length for the maximal cluster height. The good agreement is a strong argument that the experimental cluster size distribution is caused by a percolation-like trapping process (ordinary percolation). For the first time, it is demonstrated experimentally that the transition zone model proposed by Wilkinson (Phys Rev A 30:520–531, 1984) can be applied to 2D-micromodels, if bicontinuity is generalized such that it holds for the thin-film water phase and the bulk gas phase.
Persistent UFZ Identifier
Geistlinger, H., Ataei-Dadavi, I., Vogel, H.-J. (2016):
Impact of surface roughness on capillary trapping using 2D-micromodel visualization experiments
Transp. Porous Media 112 (1), 207 - 227