Cluster evolution in steady-state two-phase flow in porous media

Area of Science:

• Physics
• Earth Sciences
• Chemical Engineering

Background:

• Two-phase flow in porous media is fundamental to processes like oil recovery and CO2 sequestration.
• Understanding cluster development is key to predicting fluid distribution and transport.
• Previous models often simplified the complex dynamics of initial transients and steady-state evolution.

Purpose of the Study:

• To numerically investigate the cluster development of two-phase flow in porous media under steady-state conditions.
• To analyze the influence of capillary forces on cluster formation and distribution.
• To characterize the statistical properties of nonwetting fluid clusters.

Main Methods:

• Utilized a two-dimensional flow simulator incorporating biperiodic boundary conditions.
• Simulated initial transients and their evolution towards a steady state.
• Focused on capillary-dominated flow regimes with capillary numbers around 10(-5).

Main Results:

• Observed a crossover phenomenon where initial patterns break up before reaching steady state.
• Identified a power-law distribution (ns ~ s^(-tau)) for nonwetting cluster sizes near critical saturation, with tau = 1.92 ± 0.04.
• The determined exponent is lower than that found in ordinary percolation theory.
• Presented scaling relations and time evolution data for cluster structure and global pressure.

Conclusions:

• The study provides critical insights into the statistical mechanics of two-phase flow in porous media.
• The power-law distribution suggests scale-invariant properties of nonwetting clusters at critical saturation.
• Findings contribute to a more accurate modeling of fluid dynamics in geological formations and engineered systems.