Influence of Wetting on Viscous Fingering Via 2D Lattice Boltzmann Simulations

Abstract

We present simulations of two-phase flow using the Rothman and Keller colour gradient Lattice Boltzmann method to study viscous fingering when a “red fluid” invades a porous model initially filled with a “blue” fluid with different viscosity. We conducted eleven suites of 81 numerical experiments totalling 891 simulations, where each suite had a different random realization of the porous model and spanned viscosity ratios in the range $$M\in [0.01,100]$$ M ∈ [ 0.01 , 100 ] and wetting angles in the range $$\theta _w\in [180^\circ ,0^\circ ]$$ θ w ∈ [ 180 ∘ , 0 ∘ ] to allow us to study the effect of these parameters on the fluid-displacement morphology and saturation at breakthrough (sweep). Although sweep often increased with wettability, this was not always so and the sweep phase space landscape, defined as the difference in saturation at a given wetting angle relative to saturation for the non-wetting case, had hills, ridges and valleys. At low viscosity ratios, flow at breakthrough is localized through narrow fingers that span the model. After breakthrough, the flow field continues to evolve and the saturation continues to increase albeit at a reduced rate, and eventually exceeds 90% for both non-wetting and wetting cases. The existence of a complicated sweep phase space at breakthrough, and continued post-breakthrough evolution suggests the hydrodynamics and sweep is a complicated function of wetting angle, viscosity ratio and time, which has major potential implications to Enhanced Oil Recovery by water flooding, and hence, on estimates of global oil reserves. Validation of these results via experiments is required to ensure they translate to field studies.

A pore-resolved interface tracking algorithm for simulating multiphase flow in arbitrarily structured porous media

“…Despite the general decreasing tendency in displacement efficiency as contact angle θ 0 increases, relatively large fluctuations are observed, implying the significant inherent uncertainties due to heterogeneities in realistic porous media. The huge fluctuations in the relationship between wettability and displacement efficiency are also observed in a recent study using the lattice Boltzmann method[50]. The fractal dimension D f , on the other hand, from the theoretical perspective provides a multi-scale characterization of space filling.…”

A review of crude oil emulsification and multiphase flows in chemical flooding

“…The numerical simulation of microscopic seepage is also called micron‐scale flow simulation or pore‐scale flow simulation. The lattice Boltzmann method has been gradually developed at the microscopic scale over the last 20 years, and it has undergone rapid development in theoretical research and applications 129 . The lattice Boltzmann method is based on molecular dynamics theory, and it is used to study the mechanism of a variety of complex phenomena.…”

“…The lattice Boltzmann method has been gradually developed at the microscopic scale over the last 20 years, and it has undergone rapid development in theoretical research and applications. 129 The lattice Boltzmann method is based on molecular dynamics theory, and it is used to study the mechanism of a variety of complex phenomena. The lattice Boltzmann method has advantages, such as the ability to manage complex boundary conditions, high accuracy, good stability, simple algorithms, easy implementation of programming, and good parallel performance.…”