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Foams are dispersions of gas bubbles within a liquid. They can be generated in porous and fractured media during co-injection of two fluids in the presence of surfactants that stabilize foam bubbles. Since foam viscosity is much higher than the constituent gas and liquid phases, they are used for diverting fluid to less permeable subsurface formations in applications such as enhanced oil...
Micro-CT scans are widely used for rock models in Digital Rock Physics applications. However, up to one-half of the connected porosity of carbonates and shales is underresolved with micro-CT due to the small pore size. This underresolved pore space may still support multiphase fluid flow. To simulate two-phase flows in models where both large-scale and underresolved pores are present, we...
The precise representation of molecular motion near the three-phase dynamic contact line remains a significant research challenge [1], with substantial practical implications [2]. We investigate the two-phase flow in a pressure driven micro channel (width ~ 1µm - 10µm) having a nanometric surface roughness. The two phases are separated by an interfacial layer with surface tension, that meets...
Large-scale (TWh) renewable energy storage is crucial to achieve a net-zero green world. To accomplish this, renewable energy can be converted into hydrogen (H$_2$) and stored in large-scale volumes in giant subsurface geological reservoirs. The feasibility of underground hydrogen storage in porous reservoirs highly depends on the flow and transport behaviour of hydrogen during subsequent...
When natural gas hydrates are heated and dissolved, the boundaries of fluid-solid will apparently be changed, and average permeability and equivalent thermal conductivity change in coupling. We designed two different microstructures, grain‐coating type and pore-filling type, based on two common storage modes. The model size is 50 μm × 22 μm, and the solid particles are 2.0 μm × 2.0 μm. Then we...
Hydrogen energy is regarded as a promising energy carrier due to its high energy density and non-pollution. Solid oxide electrolysis cells (SOECs) have been studied extensively as a promising way for massive hydrogen production from renewable but unstable energy sources. The electrode microstructure of SOECs has a significant influence on their electrochemical performance. To better understand...
Digital Porous Media Analysis (DPMA) is the process of using imaging and simulation techniques (e.g., x-ray computed microtomography, Pore-Network Modelling (PNM) and Direct Numerical Simulations (DNS)) to investigate the properties of porous materials. With DPMA, physical processes are investigated in the real structure of a sample and effective porous media properties (e.g., permeability...
Abstract
As the development of medium and shallow oil and gas reservoirs progresses into the mid-to-late stages, the focus of petroleum exploration is shifting towards deep and ultra-deep reservoirs. Deep oil and gas reservoirs are defined as those with burial depths exceeding 4500 m, while ultra-deep reservoirs refer to those buried beyond 6000 m. These reservoirs exhibit...
With advances in digital rock physics, pore-scale numerical methods have been developed to estimate various petrophysical parameters based on 3D micro-CT images. However, currently pore-scale models mostly rely on segmented dry scan of the rock sample for network extraction, and the resulting network consists only of resolved pores and throats. For complex rocks such as carbonates that...
Reacting particle systems play a crucial role in various industrial applications, with limestone calcination serving as a prime example. In this process, applying high-energy input to calcium carbonate (CaCO$_3$) particles results in the production of active lime solid (calcium oxide CaO) and the by-product carbon dioxide (CO$_2$) gas. The legal obligation to mitigate CO$_2$ emissions has a...
The trapping efficiency of CO2 storage in porous subsurface is influenced by various geometric and flow characteristics. Conducting experimental studies on reservoir structure characteristic parameters and actual storage efficiency consumes a significant amount of resources, making it difficult to analyze the uncertainty of parameters through a large number of experiments. In this work, a deep...
Shale oil and gas resources are widely distributed and have abundant reserves in China, with broad development prospects and potential. Due to the inherent characteristics of shale oil, such as the large number of nanometer-sized pores with complex pore structures, significant fluid-wall effects, complex mineral compositions, abundant organic matter, and complex and diverse wettability, the...
Mineral nucleation and precipitation commonly occur in nature and plays an important role in many energy-related applications with reactive flow, especially, at pore-scale. For instance, minerals nucleate and precipitate as scale in the pore structure in unconventional reservoirs and significantly reduce the permeability of the porous media. This phenomenon could lead to a rapid decrease in...
Mineral dissolution is a common phenomenon in many subsurface geo-systems, such as carbon sequestration, wastewater disposal and oil and gas recovery. Dissolution can change the topology of porous rock, which affects the rock’s geophysical parameters, such as permeability and elastic wave velocity. We numerically investigate the relationships between the evolutions of P-wave and S-wave...
Abstract: Multiphase flow in porous media is ubiquitous in soils, oil and gas reservoirs, geologic carbon storage and hydrogen storage systems, and batteries. In recent years, direct observation using microfluidic experiments and pore-scale numerical modeling have become increasingly important tools for studying pore-scale fluid dynamics. To further examine the precision of the experiment...
The geological storage of CO2 has emerged as a critical pathway for decarbonization, where in situ carbon mineralization in mafic/ultramafic rocks such as basalts is considered the most stable form of CO2 storage. in-situ CO2 mineralization pilot projects in basaltic formations include the Wallula project in Columbia River basalt and the Carbfix project in Icelandic basalt. Multiphase flow...
Problem statement
The droplet penetration plays an essential role in various fields such as inkjet printing, fuel cells, oil and gas development, new material preparation, and enhanced heat transfer. The functions of non-wetting droplets are used to be limited due to the capillary resistance to its penetration into micropores, but the application of magnetic, electric, acoustic and optical...
In this work, a thermodynamically consistent and conservative diffuse-interface model for gas-liquid-solid multiphase flows is proposed. In this model, a novel free energy for the gas-liquid-solid multiphase flows is established according to a ternary phase-field model, and it not only contains the standard bulk and interface free energies for two-phase flows, but also includes some additional...
Immiscible two-phase flow in porous media is a universal phenomenon in various natural and industrial processes. Its invasion pattern is determined by the interplay between viscous and capillary forces, neglecting the influence of buoyancy at a small scale. In numerous scenarios in porous media, the capillary forces in drainage process are dominant, which emphasize the importance of precisely...
The Middle East has become the largest overseas oil production base of China, where marine porous carbonate reservoirs are widely-distributed. Large recoverable reserves are still unexploited, implying a great potential to obtain higher oil production. Influenced by pore type, multi-modal pore structure, initially oil-wet or mixed-wet condition, the microscopic displacement efficiency is...
The morphology of pores is an important factor influencing the permeability of porous materials[1,2,3]. In recent decades, the influence of the morphology of pores on fluid flow in geomaterials has attracted extensive attention in the engineering fields of petrochemistry, hydrogeology, civil and geotechnical structures, with applications in radioactive hazardous waste storage[4], oil and gas...
Snap-off represents a fundamental occurrence within the complex dynamics of multiphase flow in porous materials. Understanding the quantitative aspects of phenomena triggered by seismic activity within these media is vital for engineering applications and predicting natural events, particularly concerning snap-off investigations. Exploring the influence of vibrations on snap-off through...
Dissolution trapping is one of the crucial trapping mechanisms for geological carbon storage in deep saline aquifers. The injected supercritical CO2 (scCO2) flow and dissolution processes are coupled and interact with each other. Therefore, we performed direct numerical simulations in three-dimensional micro-CT images of sandstones using the volume of fluid and continuous species transfer...
Displacement of immiscible fluids in heterogeneous porous media is extensively found in many underground applications, such as groundwater remediation, underground hydrogen storage (UHS), and geological carbon storage (GCS). Natural fractures are widely distributed in the subsurface system and likely to induce a channeling effect that makes the flow within fractured porous media very distinct...
We present a theoretical study of viscous slug motion inside a microscopically rough capillary tube, where pronounced stick–slip motion can emerge at slow displacement rates. The mathematical description of this intermittent motion can be reduced to a system of ordinary differential equations, which also describe the motion of a pendulum inside a fluid-filled rotating drum. We use this analogy...
The structures we obtain with, for example, X-ray tomography imaging and then use for pore-scale imaging actually says a lot about the applicability of obtained simulated results. For example, to utilize classical homogenization scheme and obtain continuum scale properties such as permeability, relative permeabilities and numerous others, one needs to establish representativity, which is equal...
The technology of sequestering CO2 in deep shale has shown great potential due to the low permeability of shale and the high adsorption of CO2 by organic-rich characteristics. Deep shale is characterized by high-temperature and high-pressure with a significant hydro-mechanical coupling effect. The Darcy-Brinkman-Stokes method was integrated with heat transfer equations to simulate...
Porous media coupled with free-flow systems are prevalent in both natural and technical applications. A classic example of such systems in the nature is the interaction between wind and partly saturated soil, leading to soil drying through evaporation. In fuel cells, as an example of technical applications, the understanding of interface process between the free flow (gas distributor channel)...
Extreme viscosity ratios emerge in many important applications such as carbon dioxide geological sequestration (CO2 is much less viscous than formation fluids), natural gas production and hydrogen storage (gas is much less viscous than water), and heavy oil reservoir recovery (oil is much more viscous than water). Clearly understanding the immiscible two-phase flow with extreme viscosity ratio...
In shale nanoscale pores, the CH4 molecular size is equivalent to the mineral molecular size, then, the non-negligible gas-solid molecular interactions lead to the existence of a large amount of adsorbed gas with low mobility, which has an important impact on shale gas production. Since the adsorption capacity of CO2 is higher than that of CH4, the injected CO2 can be adsorbed on the mineral...
Geological carbon sequestration is the most suitable way to alleviate the negative influence caused by CO2 at the field scale. CO2 dissolution as one of the most indispensable and predominant trapping mechanisms is a complicated process involving both physical and chemical phenomena. In this work, CO2 dissolution after capillary trapping far away from the injection well under different...
In polymer electrolyte membrane water electrolyzers (PEMWE) and polymer electrolyte membrane fuel cells (PEMFC), efficient electrochemical reactions depend on the optimal flow of water and oxygen within porous electrodes. However, a significant challenge arises due to concentration losses, also known as diffusion overpotential or mass transport overpotential (Vdiff). This phenomenon is...
