Imaging and Modeling Multiphase Flow and Reactive Transport in Disordered Porous Media: Spatio-Temporal Complexities

Understanding of multiphase flow, transport and reaction phenomena in disordered porous media has recently been transformed by the advances in X-ray and NMR imaging, which inspired new concepts in pore-scale modeling. More accurate static and dynamic experimental description of solid and fluid(s) distributions in the pore space enabled simplifications in descriptions of spatio-temporal complexities through introduction of the intrinsic functions characterizing flow, transport and reaction in the form of distributions, rather than average values.

This concept is illustrated by the predictive modeling of flow and transport on micro-CT images of subsurface porous media validated against NMR experiments. Furthermore, a novel set of ideas used for characterising physical and chemical heterogeneity and their coupled impact on the effective reaction rates and dissolution patterns in multi-mineral porous media will be discussed.

One of the key breakthroughs was achieved by devising differential imaging tomography which provides full information of connectivity at sub-micron scale. Examples will be provided for multi-modal function description of single phase flow and transport, characterisation of initial and recovered oil from micro-porosity in steady-state two-phase flow, and determination of capillary-number dependent flow intermittency.

Furthermore, advances in in-situ characterisation of pore morphology and wettability will be presented, where a distinct pore-morphology signature is identified for unconsolidated and consolidated media. Both pore morphology and wettability have a large impact on the potential for layer flow. A distinct mixed-wet state can be identified where two fluid phases remain connected over a wide range of saturation. This state can be designed to improve oil recovery, the performance of batteries, fuel cells, catalysts, and other disordered porous materials.