The percolation of acidic fluids through natural rocks (e.g. CO2 storage, Karst formation, geothermal formation) induces chemical reactions of dissolution and/or precipitation, which consequently alter the structural and hydrodynamic properties of the rock. These reactions are not uniformly distributed but instead become localized based on various local parameters, such as fluid velocity...
Access to clean water is one of today’s major global challenges. Human health, food production and biodiversity all rely on groundwater, yet this vital resource is increasingly exposed to soil pollution. Substances such as pesticides, fertilizers, plastics and industrial chemicals seep into the ground and travel downwards with rainwater. Before reaching groundwater, pollutants must pass...
Depleted carbonate reservoirs are promising sites for geological CO2 storage, yet the presence of residual hydrocarbon introduces complex pore-scale interactions that influence the dynamics of solid dissolution. We combined time-resolved X-ray microtomography (micro-CT), core-flooding experiments, and pore-scale modeling to investigate how residual hydrocarbon affects dissolution patterns and...
Basaltic formations represent promising geological reservoirs for permanent CO2 storage through mineralization, yet their unique pore architecture and reactive transport dynamics differ fundamentally from conventional sandstone systems. This study integrates experimental flow-through investigations with multiscale characterization and pore-network analysis to elucidate the coupled mechanisms...
Fracture networks are widespread in subsurface reservoir rocks and act as primary pathways for reactive solute transport. Reactive transport processes in fracture networks show critical role in governing the efficiency of subsurface energy storage and exploitation, such as CO₂ sequestration and geothermal resource development, as well as on the long-term safety of radioactive waste disposal....
Chemical and biological processes across natural and engineered porous media are often controlled by the mixing of solutes by fluid flow. Theoretical descriptions of mixing dynamics are currently largely limited to steady flows in fully or partially water-saturated environments. In contrast, in dynamic multiphase flows, fluid interfaces move in time, leading to persistent rearrangement of flow...
We study the effect of connectivity of two-dimensional heterogeneous porous media on
flow and transport by looking at line stretching and dispersion. A fluid is stirred by the
porous medium structure that leads to spatial flow variability and the deformation of fluid
elements. These mechanisms have been thoroughly analyzed in previous articles [Comolli
et al. (2019), Dentz et al. (2016b)...
The unsaturated zone of soils, spanning from the surface to deeper aquifers, mediates exchanges of water, heat, and solutes, and plays a critical role in nutrient transfer and resource availability. Yet, the physical mechanisms governing mixing between infiltrating solutions and resident fluids under unsaturated conditions remain poorly understood. We address this gap through pore-scale...
At all scales, porous materials stir interstitial fluids as they are advected, leading to complex distributions of matter and energy. Of particular interest is whether porous media naturally induce chaotic advection in Darcy flows at the macroscale, as these stirring kinematics profoundly impact basic processes such as solute transport and mixing, colloid transport and deposition, chemical...
Porous media, whether found in natural aquifers or engineered in industrial columns, encompass a vast range of interwoven length scales. These nested scales span more than twelve orders of magnitude—from nanometers to kilometers—making porous media one of the most striking examples of multiscale systems in nature. The central challenge in understanding fluid flow and transport in such media...
Dissolution in porous media and fractured rocks alters both the chemical composition of the fluid and the physical properties of the solid, with major implications for permeability evolution, injectivity, and long-term transport [1]. Depending on the balance between advection, diffusion, and surface reaction, reactive flow may enlarge pores uniformly, widen pre-existing channels, or trigger...
Porous reactors and multiphase systems are ubiquitous in chemical engineering, spanning packed-bed catalysis, coated monoliths, foam catalysts, membranes, and electrochemical devices. In these systems, macroscopic performance is governed by the close relationship between the intrinsic kinetics and transport phenomena occurring across widely separated length scales: advection, dispersion, and...
Cerebral function is highly dependent on a continuous blood supply of oxygen and nutrient. Depending on its duration and intensity, any disruption of blood supply can lead to progressive neurodegeneration and cognitive decline. For instance, Alzheimer’s disease (AD) patients are subject to a chronic decrease of cerebral blood flow (CBF) which is believed to induce tissue hypoxia and further...
Underground hydrogen storage typically relies on a cushion gas to stabilize reservoir pressure during cyclic injection, production, and storage. When CO2 is used as a cushion gas, interactions between CO2, H2, and resident brine may influence storage in heterogeneous porous rock.
To investigate this, we conducted microfluidic drainage and imbibition experiments using an equilibrated H2/water...
Efficient solute mixing in porous media is essential for a wide range of natural processes and industrial applications, including nutrient transport in biological systems, groundwater bioremediation, carbon dioxide–enhanced oil recovery, and packed-bed reactors. The degree of solute mixing directly governs the rates of associated biological and chemical reactions. Although turbulence is widely...
This study examines the spatiotemporal evolution of laminar plumes propagating through a vertically density-stratified porous medium under Darcy flow conditions at high Peclet numbers ($\mathrm{Pe} \gg 1$). Density stratification is ubiquitous in natural subsurface environments and plays an important role in controlling plume migration, spreading, and mixing. Such conditions arise in a wide...
Heterogeneous porous media saturated with two liquid phases represent a complex system that can be observed in many engineering and natural processes. The transport of passive solutes in this type of environment is at the centre of our research whose final goal is to quantify and mathematically describe the physical mechanisms that regulate the displacement of the solute, such as stretching...
Solute mixing often occurs in multiphase flows within the vadose zone, where drainage and imbibition alternately saturate and desaturate the porous substrate. While our understanding of mixing in porous media has rapidly advanced to encompass steady multiphase flows, our knowledge remains incomplete in dynamic multiphase flows such as drainage and imbibition, where the bursty movements of...
We analyze the impact of permeability heterogeneity on reactive buoyancy-driven convective dissolution in the case of a bi-molecular $\mathrm{A} + \mathrm{B} \to \mathrm{C}$, which leads to different non-monotonic density profiles. We compare the reaction and mixing dynamics between homogeneous permeability fields and heterogeneous scenarios consisting of horizontally stratified, vertically...
Understanding the way that mixing during transport in porous media governs the kinetic rate of bi-molecular reactions has grown through original experiments and new theories. A long-awaited expansion in the set of controlled experiments now inspires broader testing of proposed theories. Here we apply our ballisticule-based quasi-closed form solution to mixing-limited reactive transport...
Hydrodynamic transport in rough-walled geological fractures is governed by the strong spatial heterogeneity of the aperture field. Even in the purely advective limit, this heterogeneity produces pronounced velocity intermittency along streamlines, with fluid particles alternating between fast channelized regions and extended low-velocity or quasi-stagnant zones. Such intermittency generates...
Solute transport in porous media is a fundamental process in various applications, yet the influence of fluid characteristics is often overlooked. When the viscosity ratio, defined as $M=\mu_{\text{displaced}}/\mu_{\text{displacing}}$, exceeds unity, the displacement becomes hydrodynamically unstable and gives rise to viscous fingering. Under such adverse viscosity ratio conditions ($M>1$),...
Geomaterials are complex porous materials presenting a wide diversity of structures, which set how a fluid will flow through it. The understanding of the mechanisms controlling the flow kinematics at the pore scale is however decisive to predict and control transport processes (dispersion and mixing). Using index matching techniques, one can develop transparent porous media to perform direct...
Measurements of water isotopes are often used to infer water resident times in a catchment and to estimate the thickness of aquifer storage zones. Because isotopic variants of water (e.g., D₂O, H₂¹⁸O) are generally assumed to behave identically to water molecules (H₂O), they are often considered to be fully representative of actual water movement and are preferred over inert chemical tracers...
The inherent heterogeneity of the subsurface strongly affects the heat transport behaviour and remains a critical challenge in geoscience and related industrial applications. Capturing this behaviour requires resolving the interplay between advection, conduction, and the structural complexity of porous media. In this study, we investigate pore-scale thermal dynamics through laboratory...
We investigate the role of the fluid properties on convective mixing in confined porous media. We consider two miscible fluid layers in which the density of the fluid is controlled by the presence of a solute, quantified by its value of concentration. When these fluids combine, the density of the resulting mixture increases, originating hydrodynamic convective instabilities that further...
Mixing induced reactions play a key role in a wide range of applications, including contaminant transport and remediation, carbon and hydrogen storage, etc. The stretching of the resulting front developed at the interface between two miscible and reacting fluids caused by flow heterogeneities plays a central role in controlling the spatial extent of reaction and its effective rate. Since shear...
The transport of flexible fibers through complex environments, such as porous and structured media, occurs in a variety of systems such as textile microplastics in soils or fibers in small cracks of natural rocks. Additionally, particle sorting or separation using structured media, such as pillar arrays, is essential to many processes, such as diagnosis, biological analysis, and environmental...
Heterogeneous porous media are found in many engineering and natural processes, either by design to improve the efficiency of the system, or as a consequence of the process itself. Here, we focus on dispersive transport in porous media displaying spatiall evolving heterogeneities, characterized by continuous spatial variations of their properties.
Using upscaling, we derive the macroscopic...
