The change in contact angles due to the injection of low salinity water or
any other wettability altering agent in an oil-rich porous medium is modeled by
a network model of disordered pores transporting two immiscible fluids. We
introduce a dynamic wettability altering mechanism, where the time dependent
wetting property of each pore is determined by the cumulative flow of water
through it. Simulations are performed to reach steady-state for different
possible alterations in the wetting angle (θ). We find that deviation
from oil-wet conditions re-mobilizes the stuck clusters and increases the oil
fractional flow. However, the rate of increase in the fractional flow depends
strongly on θ and as θ→90∘, a critical angle, the system
shows critical slowing down which is characterized by two dynamic critical
exponents.Comment: 8 pages, 9 figure