Oil/water displacement in microfluidic packed beds under weakly water-wetting conditions: competition between precursor film flow and piston-like displacement

Yukie Tanino* (Corresponding Author), Xanat Zacarias Hernandez, Magali Christensen

*Corresponding author for this work

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30 Citations (Scopus)
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Optical microscopy was used to measure depth-averaged oil distribution in a quasi-monolayer of crushed marble packed in a microfluidic channel as it was displaced by water. By calibrating the transmitted light intensity to oil thickness, we account for depth variation in the fluid distribution. Experiments reveal that oil saturation at water breakthrough decreases with increasing Darcy velocity, UwUw , between capillary numbers Ca=μwUw/σ=9×10−7Ca=μwUw/σ=9×10−7 and 9×10−69×10−6 , where μwμw is the dynamic viscosity of water and σσ is the oil/water interfacial tension, under the conditions considered presently. In contrast, end-point (long-time) remaining oil saturation depends only weakly on UwUw . This transient dependence on velocity is attributed to the competition between precursor film flow, which controls early time invasion dynamics but is inefficient at displacing oil, and piston-like displacement, which controls ultimate oil recovery. These results demonstrate that microfluidic experiments using translucent grains and fluids are a convenient tool for quantitative investigation of sub-resolution liquid/liquid displacement in porous media.
Original languageEnglish
Article number35
JournalExperiments in Fluids
Early online date24 Jan 2018
Publication statusPublished - Feb 2018

Bibliographical note

This paper contains work supported
by the Royal Society Research Grant RG140009. XZH was
supported by the Mexican National Council for Science and
Technology, Mexico. The authors gratefully acknowledge Stephen
A. Bowden for the absorption spectra (Fig. 3), Bernard Kombe
for measuring the permeability of the packed beds and for his
contribution to one of the microfluidic experiments, Munasuonyu
Walter for the SEM image of crushed marble (Fig. 1)
originally published in Bowden et al. 2016, Luca Romanello
for providing unpublished viscosity and density measurements
from his MSc thesis (Romanello, 2015), Aleksei Gunkin for
his insights on post-processing, Paul Hallet for allowing MC
access to their tensiometer, and Corex (UK) Ltd. for allowing
Luca Romanello and MC access to their viscometer. We thank
the three anonymous reviewers for their detailed comments.
Open Access via Springer Compact Agreement.


  • film flow
  • pore-scale imaging
  • multiphase flow
  • porous media
  • imbibition
  • fingering
  • roughness


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