Pore-scale Ostwald ripening of gas bubbles in the presence of oil and water in porous media
Peer reviewed, Journal article
Published version
Permanent lenke
https://hdl.handle.net/11250/3072334Utgivelsesdato
2023Metadata
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Originalversjon
Singh, D., Friis, H. A., Jettestuen, E., & Helland, J. O. (2023). Pore-scale Ostwald ripening of gas bubbles in the presence of oil and water in porous media. Journal of Colloid and Interface Science, 647, 331-343. 10.1016/j.jcis.2023.05.070Sammendrag
Hypothesis
Ostwald ripening of gas bubbles is a spontaneous mass transfer process that can impact the storage volume of trapped gas in the subsurface. In homogeneous porous media with identical pores, bubbles evolve toward an equilibrium state of equal pressure and volume. How the presence of two liquids impacts ripening of a bubble population is less known. We hypothesize that the equilibrium bubble sizes depend on the surrounding liquid configuration and oil/water capillary pressure.
Method and numerical experiments
We investigate ripening of nitrogen bubbles in homogeneous porous media containing decane and water using a level set method that alternately simulates capillary-controlled displacement and mass transfer between bubbles to eradicate chemical-potential differences. We explore impacts of initial fluid distribution and oil/water capillary pressure on the bubble evolution.
Findings
Ripening in three-phase scenarios in porous media stabilizes gas bubbles to sizes that depend on their surrounding liquids. Bubbles in oil decrease in size while bubbles in water increase in size with increasing oil/water capillary pressure. Bubbles in oil reach local equilibrium before the three-phase system stabilizes globally. A potential implication for field-scale gas storage is that the trapped gas fractions in oil and water vary with depth in the oil/water transition zone.