Investigating erosion effects on reservoir rock properties via micro-continuum framework

Reservoir rock erosion critically impacts subsurface energy harvesting processes, particularly under long-time water flooding. Extended fluid exposure weakens rock matrices, inducing grain detachment and mobilization. This erosional process fundamentally modifies pore-scale geometry and enhances porosity, permeability, and reshapes preferential flow pathways. However, the multiscale relationship between microscale erosion dynamics and continuum-scale effective properties (e.g., porosity, absolute/relative permeability) remains poorly understood, hindered by the scale disparity between sub-micron mobilized particles and macroscale reservoir models. Current methods struggle to reconcile this crucial gap, as conventional continuum-scale descriptors inadequately capture sub-resolution particle transport and its cascading impact on flow properties. To address this, we present a multiscale investigation using the Micro-Continuum Method (MCM) to resolve the interplay between pore-scale erosion mechanisms and reservoir-scale multiphase flow behavior in heterogeneous porous media. Through systematic numerical experiments, we quantify how three critical factors-(1) erosion directionality, (2) inherent media heterogeneity, and (3) erosional boundary conditions-govern the evolution of pore geometry and resultant effective properties. Our results demonstrate that erosion-driven pore restructuring significantly alters hydraulic properties, with preferential grain removal creating localized high-permeability channels that dominate flow regimes. The MCM framework successfully bridges scales, capturing coupled processes of particle mobilization, transport, and multiphase flow feedbacks. These insights advance predictive modeling of formation damage and fluid recovery in energy systems, offering a robust tool to optimize subsurface operations in erosion-prone reservoirs.