InterPore2026

Direct Pore-Scale Simulation of the Origins of Intermittency in Multiphase Flow

20 May 2026, 15:35

1h 30m

Poster Presentation (MS09) Pore-Scale Physics and Modeling Poster

Speaker

Sasha Karabasova (Imperial College London)

Description

Experimental studies have identified an intermittent multiphase flow regime in porous rocks that emerges between classical Darcy flow and ganglion dynamics, characterised by persistent flow pathways coexisting with localised regions of transient phase switching. Despite its relevance to subsurface energy applications such as carbon storage and hydrogen transport, the pore-scale origins of this intermittency remain poorly understood and have not yet been predicted using direct numerical simulation (DNS).

In this work, we investigate the emergence of intermittent flow directly at the pore scale using high-resolution DNS of immiscible two-phase flow in three-dimensional rock images. The simulations are performed on segmented micro-CT images of natural porous media, allowing the intrinsic geometric and topological heterogeneity of real rocks to be preserved. Flow is driven through the pore space under controlled capillary and viscous conditions, enabling systematic exploration of regimes spanning linear Darcy flow through the onset of intermittency.

Time-resolved simulation outputs are analysed to identify localised regions exhibiting transient phase occupancy, or “flip-flopping,” while surrounding pathways remain hydraulically stable. These dynamics are quantified using temporal saturation statistics, pressure fluctuations, and flow pathway persistence metrics. The results demonstrate that intermittency can arise prior to large-scale ganglion mobilisation and is strongly localised within specific pore-scale environments rather than uniformly distributed across the domain.

Comparisons with experimental observations reported by Spurin et al. (2021) are used to guide the interpretation of simulated flow behaviour, particularly in terms of the spatial localisation and temporal characteristics of intermittent regions. The simulations are designed to examine how pore-scale geometry and structural heterogeneity influence the emergence and localisation of intermittent phase switching.

By providing a direct numerical analogue to experimentally observed intermittent flow, this work establishes a foundation for linking pore-scale structure to non-Darcy multiphase flow behaviour. These insights are relevant for improving predictive models of multiphase transport in subsurface energy systems, including carbon capture and storage, hydrogen storage, and geothermal reservoirs, where intermittent flow may impact effective permeability, trapping, and flow stability.