Presentation materials
A less viscous fluid invading into a more viscous immiscible fluid produces fingering patterns due to instabilities at the interfaces between them. In the space between two closely spaced parallel plates, the fingers appear to be smooth as there is essentially only one interface separating the fluids. In case of a porous medium, e.g. by filling the space between the plates with fixed glass...
Mineral dissolution is relevant to most subsurface processes, including CO2 storage, geothermal systems and enhanced oil recovery. Pore-scale simulation can be a useful tools to decipher the reactive transport within the pore-space and estimate upscaled parameters such as permeability and reaction constants. These simulations may be challenging though as they involve the tracking of multiple...
Compositional flow and phase change dynamics in porous media play a central role in many industrial and geoscience applications including fuel cells, geologic CO2 sequestration, and hydrocarbon production. Though the interplay between transient two-phase flow and phase change dynamics is of critical important, it remains not well understood limited by computational challenges especially for...
For nanoconfined fluids, equilibrium properties such as adsorption, density, and surface diffusion are dependent on the layered structure of the fluid near the surface. This layered structure is also relevant to describe transport as the noncontinuum effect, such as slip velocity, depends on the near-wall density. While molecular dynamics simulations quantify the layered density profile in...
Pore space properties such as pore shape, connectivity and pore size distribution are key to understanding pore-scale processes. X-ray computed (micro-) tomography (µCT) has become one of the dominant techniques to non-destructively investigate this pore space in three dimensions.
In conventional attenuation-based µCT, the rule of thumb is that the achievable resolution is about three orders...
In various natural and engineered systems, multi-phase flow and mineral-fluid interactions co-occur and their interplay controls the evolution of these systems. In continuum scale models, how multiphase flow dynamics affect mineral reactions are rarely accounted for or are corrected via reactive surface area and saturation of the aqueous phase. To evaluate the applicability of such treatment,...
Low resistivity pays (LRPs) are reservoirs from which dry hydrocarbons are produced in the presence of erroneously interpreted water saturations. LRPs are often identified within laminated reservoir sequences, shaley lithologies, and formations with multi-modal pore-size characteristics or containing fresh formation waters identified on the basis of well logging, testing and core observations....
Over the past years, tomographic scanning techniques like micro-CT have enabled the acquisition of high-fidelity void-space geometries of natural porous media [e.g., Raeini, Bijeljic, and Blunt, Physical Review E, 96, 1 (2017)]. There are, however, experimental/computational limitations in the sample size, respectively level of detail or voxel count, that can be acquired [Section 2.3 in Cnudde...
Nucleation is the first step of any mineral precipitation and crystal growth process. It is often overlooked in studying the reactive transport phenomena. Nucleation controls the location and timing of crystal formation in a porous structure. The spatial distribution of stable secondary nuclei is crucial to predict hydrodynamics of the porous medium after mineral precipitation precisely. To...
In this study, a pore-network model as an upscaled representation of the pore space and fluid displacement is used to simulate and predict two-phase flow through porous media. The results of micro-CT pore-scale imaging experiments are used to calibrate the model, and specifically to find the pore-scale distribution of wettability. As wettability is an uncertain parameter in two-phase flow...
Drying in porous media is a complicated multi-physical process including liquid/vapor multiphase flow, phase change and heat and vapor transport, occurring with the complex geometry of porous media. Contact angle hysteresis induced by surface roughness is shown to influence drying of liquid or colloidal droplet, resulting in a stick-slip drying mode and the formation of coffee ring after...
Coupled free-flow and porous-medium systems described by the Stokes-Darcy equations are intensively studied in the last decade. Most of the coupling concepts are based on the Beavers-Joseph interface condition, which is developed for one-dimensional flows parallel to the fluid-porous interface. However, this condition is unsuitable for arbitrary flow directions [2], e.g. for industrial...
Plant roots and bacteria alter the soil physical properties by releasing a polymeric blend of substances (e.g. extracellular polymeric substances and mucilage). Despite experimental evidence of the impact of such polymer solutions on water fluxes across the root zone, the physical mechanisms controlling the spatial distribution in complex porous media (soils) have not yet been addressed. In...
Multiphase flow in porous media is a subject with important technical applications, such as in oil recovery from petroleum reservoirs or in Liquid Composite Molding Processes. In the Liquid Composite Molding and in other applications, macroscopic resin flow is modelled by postulating a multiphase generalization of Darcy’s law. However, modelling of multiphase flow remains an important...
We expect quantitative changes in the behavior of immiscible two-phase flow in porous media when we move from uniform to mixed wet conditions [1]. Are there also qualitative changes? When viscous and capillary forces -the latter determined by the wetting conditions - compete, there is growing evidence that the flow rate depends on the pressure gradient to a power in the the range 1.5 to 2...
Imbibition – the process of a wetting fluid displacing a nonwetting fluid in porous media – profoundly affects geochemical reaction networks in stimulated geological formations. Current quantitative models of fluid transport in such formations widely assume that imbibition of fluids into porous media occurs on a faster time scale than geochemical reaction front evolution. This assumption...
Pore scale simulation is increasingly used to study various phenomena that cannot be reproduced by conventional Darcy-based simulators. Direct Numerical Simulation (DNS) on systems larger than few millimeters is too computationally demanding. Pore Network Modeling (PNM) is a practical way to study the flow at pore scale on larger volumes while keeping reasonable running times.
Recent...
Due to the continuous depletion of conventional oil reservoirs, as an unconventional reservoir, shale plays an increasingly important role to meet the ever-growing global energy demand. Thanks to the extensive number of nano-scale pores and ultra-narrow pore throats (sub-2 nm), shale media is typically subject to an ultra-low permeability. The presence of ultra-narrow pore throats in shale...
Pore scale simulation of reactive flows is a challenging and computationally intensive problem, especially in the case of complex reactions. In many applications, the complicated chemical reactions are handled via coupling a transport solver to a proper software tool for chemistry, e.g., such as ChemKin, Phreeqc. Reactoro. The practice, however, shows that such simulations can be very time...
In the frame of a project aiming to develop a multi-scale imaging and modelling procedure for reactive transport in porous media, we present our first results concerning diffusion and reaction. For the problems we consider, heterogeneous reactions are dominant, meaning that the reactive part of the fluid/solid interface must be precisely described at the local scale. On the other hand, the...
Multi-phase flow and transport in porous media is prevalent in a wide range of challenging fluid mechanics problems in sustainability, energy, and the environment. Accurate prediction of the displacement and interaction of such flows is vital in addressing these problems, particularly the small- or pore-scale study of the flow's spatial and temporal evolution, which can impact flow behavior at...
Ostwald ripening phenomenon is particularly important for foam EOR and geological CO
Abstract: Pore scale immiscible displacement is crucial in oil industry. The surface roughness of throat is an important factor affecting water-oil interface movement. In this paper, the Navier-Stokes (N-S) equation coupled with the phase field method is adopted to analyze the oil-water flow and interface movement in single channel, considering different surface roughness, diverse...
In the field of high temperature applications such as energy conversation processes based on concentrated solar heating or the design of thermal protection systems for space vehicles, porous materials with high porosity (75-95 %) know today a growing interest. Two categories of porous materials which can be commonly described by an interconnected network of solid constituents surrounded by a...
When dealing with pore scale simulation, two main methods are generally used: direct numerical simulation (DNS) and Pore Network Modeling (PNM). The former can use different formalism like Lattice-Boltzmann, Navier-Stokes or Smoth-Particule-Hydrodynamics. While DNS can provide more precise results than PNM, it cannot get reliable results on multiphase flow on images exceeding 500^3 voxels. On...
Multiphase flow properties such as the capillary pressure and the relative permeability are a crucial parameter for subsurface evaluation and engineering such as oil & gas development and CCS projects. The measurement of the relative permeability of unconsolidated rocks is extremely difficult due to the collapse of samples and the influence of changes in the internal structure due to particle...
A thorough understanding of pore-scale modelling techniques is essential to flow through permeable media research. We compare two phase-flow simulations from the generalised network model (GNM) [Raeini et al, 2017, 2018] with a recently developed lattice-Boltzmann model (LBM) [Akai et al, 2018, 2020] for drainage and waterflooding in two samples — a synthetic beadpack and a micro-CT imaged...
Mixing-controlled reactions govern various systems, and play a central role in many industrial applications (e.g., CO2 sequestration and microbially-induced calcite precipitation). However, at-scale models are limited in simulating such processes with high fidelity and computational efficiency, especially in describing those reactively “hot spots” that often occur at fundamental scales but...
The wetting condition of the reservoir is known to have a big impact on oil recovery by waterflooding and wettability alteration has been widely accepted as one major mechanism of many enhanced oil recovery techniques. However, it remains not fully clear what wetting conditions lead to the maximum oil recovery, and there were seemingly contradictions between different studies in terms of the...
The surging demand for energy and the environmental impacts of conventional sources such as fossil fuels are the ground for the upcoming predicted energy crisis. Electrolysis of water has emerged as a promising technology for surplus production and storage of pure hydrogen as an alternative green fuel. Polymer Electrolyte Membrane (PEM) water electrolysers are used for the on-demand power...
Fluid mechanics simulations of flow through porous media frequently use the Lattice Boltzmann Method (LBM) due to its compatibility with experimentally determined volumetric images of porous media. However, the use of the LBM does present challenges including accuracy of the fluid/solid interface and complexity of determining Lattice Boltzmann formulations for varying transport models....
We investigate the Brinkman equation for modelling free flows over porous media. Using scaling estimates we show that the Brinkman viscosity
where
The new constraints for reducing hazardous emissions and sustainable fuel production led to an increased usage of ultra-low-sulfur diesel (ULSD) and bio-diesel. Such fuels have a significantly lower surface tension coefficient in comparison to Diesel. Consequently, the design of separators in diesel fuel filters meeting today’s performance requirements imposes a challenge to the developing...
