Dynamic wettability alteration in immiscible two-phase flow in porous media: Effect on transport properties and critical slowing down

TL;DR

This paper models how dynamic wettability changes in porous media affect flow properties, revealing a critical angle where flow dynamics slow dramatically, with implications for enhanced oil recovery.

Contribution

It introduces a dynamic wettability alteration mechanism based on flow history and identifies a critical angle causing slowing down in flow dynamics.

Findings

Re-mobilization of stuck clusters increases oil flow.

Flow rate dependence on wettability angle is significant.

Critical slowing down occurs near 90° contact angle.

Abstract

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 ($\theta$). 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 $\theta$ and as $\theta\to 90^\circ$, a critical angle, the system shows critical slowing down which is characterized by two dynamic critical exponents.