Local Statistics of Immiscible and Incompressible Two-Phase Flow in Porous Media

TL;DR

This paper investigates the local statistical properties of steady-state two-phase flow in porous media, demonstrating size-independent distributions of flow and saturation within a Representative Elementary Area, paving the way for continuum-scale modeling.

Contribution

It introduces a statistical analysis of flow fluctuations in a pore network model, showing distributions become independent of system size, enabling local differential equation descriptions.

Findings

Flow rate and saturation distributions become size-independent in large models.

Statistical independence supports development of continuum-scale models.

Pore-scale fluctuations can be characterized statistically for large systems.

Abstract

We consider immiscible and incompressible two-phase flow in porous media under steady-state conditions using a dynamic pore network model. We focus on the fluctuations in a Representative Elementary Area (REA), with the aim to demonstrate that the statistical distributions of the volumetric flow rate and the saturation within the REA become independent of the size of the entire model when the model is large enough. This independence is a necessary condition for developing a local statistical theory for the flow, which in turn opens for the possibility to formulate a description at scales large enough for the typical pore size to be negligible using differential equations.