Oil Recovery from Micropatterned Triangular Troughs during a Surfactant Flood

We
study the recovery of oil trapped inside micropatterned triangular
troughs after injecting a surfactant solution. In our experiments,
we track the trapped oil volume with duration of surfactant flood
for different capillary numbers. We observe that the capillary number
affects the amount of oil recovered as the well as the rate of oil
recovery. We employ multiphase flow simulations to analyze our system
and show a qualitative agreement between the simulations and experimental
results. We also discover that beyond a capillary number, the volume
of oil recovered plateaus, and no additional oil is released with
an increase in capillary number. We develop a theoretical model to
predict the dependence of maximum oil recovery on geometrical features
and find that the theoretical predictions compare favorably with the
trends obtained from our simulations. Though approximate, theoretical
relation provides insights into the efficiency of oil recovery and
can be utilized to understand the effect of sharp bends and dead ends
in enhanced oil recovery and soil remediation.