Snap-off is an important dynamic multiphase flow phenomenon which occurs in porous media. It plays a dominant role in the residual trapping and mobilization/immobilization of nonwetting fluids such as hydrocarbons or CO₂. Current studies, applications, and threshold criteria of snap-off are mostly based on static or equilibrium conditions. Thus, the dynamics of snap-off which is relevant for many real world applications has rarely been systematically studied. While a static criterion indicates the snap-off potential for nonwetting fluids, the competition between the time required for snap-off and the local pore throat capillary number determines whether snap-off actually occurs. Using a theoretical model to couple the wetting film thickness to the local capillary number at the pore throat, we analyzed the dynamics of the wetting/nonwetting interface instability in sinusoidally constricted capillary tubes. The influence of dynamic factors as encapsulated by the effect of local capillary number on nonwetting fluid snap-off time were investigated for varying pore throat to pore body aspect ratio and pore body distances. The analysis showed that snap-off can be inhibited by a sufficiently large local capillary number even in cases where the static snap-off criterion has been met.
W. Deng et al., "Influence of Dynamic Factors on Nonwetting Fluid Snap-Off in Pores," Water Resources Research, vol. 51, no. 11, pp. 9182-9189, American Geophysical Union (AGU), Nov 2015.
The definitive version is available at https://doi.org/10.1002/2015WR017261
Civil, Architectural and Environmental Engineering
Keywords and Phrases
Aspect ratio; Carbon dioxide; Film thickness; Interfaces (materials); Multiphase flow; Porous materials; Wetting; Capillary numbers; Dynamic factors; Equilibrium conditions; Interface Instability; Non-wetting fluids; OFF time; Pore scale; Theoretical modeling; Capillarity; Carbon dioxide; Hydrocarbon; Hydrological modeling; Immobilization; Mobilization; Multiphase flow; Porous medium; Local capillary number; Snap-off time
International Standard Serial Number (ISSN)
Article - Journal
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