Swelling of Shale-rocks create several problems [1] during underground drilling operations, such as stuck-pipe/drill-bit. However, swelling of shale-rocks can close the gaps between rock (wellbore) and casing –therefore no cementing is needed – which can save a lot of time and money and such a “natural” closing ensures “no-leakage” during further drilling and production phases. The field...
A major challenge in flow through porous media is to better understand the link between pore-scale microstructure and macroscale flow and transport. For idealised microstructures, the mathematical framework of homogenisation theory can be used for this purpose. Here, we consider a two-dimensional microstructure comprising an array of circular obstacles, the size and spacing of which can vary...
The use of conventional techniques for soil stabilization often involves chemical compounds which are not environmentally friendly and can be hazardous. Moreover, newly introduced regulations which target zero CO2 emission demand new construction policies and alternative construction solutions. When it comes to soil improvement, reducing the level of greenhouse gas emission would mean...
An innovative analytical 2D model for solvent injection-based heavy oil recovery was generated with respect to complicated mass transfer mechanisms integrating diffusion and dispersion, dynamic viscosity reduction, and fluids mixture expansion. The high nonlinear process caused by coupled diffusion and fluids movement, viscosity reduction, and mixture volume expansion were analytically...
Bacillus subtilis is a well-known plant-growth-promoting-rhizobacteria (PGPR). It has been suggested that PGPR influences the hydro-physical properties of soil, but the mechanistic understanding of this is still scarce. As a stress-tolerant-bacteria, Bacillus subtilis can produce biosurfactant to create surface-tension and viscosity gradient and thus form and spread visco-elastic biofilm...
CO2-plume geothermal (CPG) operations are considered for sufficiently permeable formations. Fluvial sedimentary reservoirs affect losses in pump energy in heat extraction from hot sedimentary aquifers (HSA). It has been shown previously that the losses for heat extraction from HSAs can be reduced by up to 10% by orienting a doublet well pair parallel to the paleo flow trend rather than...
The interplay between chemical and transport processes can give rise to complex reaction fronts dynamics, whose understanding is crucial in a wide variety of environmental, hydrological and biological processes, among others. An important class of reactions is A+B$\to$C processes, where A and B are two initially segregated miscible reactants that produce C upon contact. Depending on the nature...
Geochemical reactions in porous media can result in various patterns of flow channels and fractures which could potentially alter the properties of the porous media including porosity, permeability, tensile strength and tortuosity, etc. Enhancing our knowledge of these reactions at pore scale can help better predict the impacts of these reactions on the larger scales. Mineral surface area, as...
Characterization of irreducible saturation of the wetting phase during multiphase fluid flow in porous media is essential for an accurate estimation of CO2 storage capacity and hydrocarbon recovery of the geological formations. Despite pore deformation has been shown to significantly control single-phase and multiphase fluid flow in porous media, the interactive controls of capillary number...
Low salinity waterflooding (LSWF) as an enhanced waterflood technique is applicable in secondary and/or tertiary oil production. The performance of LSWF depends on different factors including the volume of injected brine, its salinity and in-situ mixing. Mixing is intensified due to adverse mobility ratio at low salinity (LS) - high salinity (HS) front. This research focuses on the impact of...
The heterogeneity of natural geologic samples presents significant challenges in furthering our understanding of geochemical reactions in porous media. This investigation explores the feasibility of fabricating reactive rocks through novel additive manufacturing techniques by integrating reactive materials with polymer filaments. Using 3D X-ray Computed Tomography (X-ray CT) images of a...
The dissolution of fractures exhibits various patterns when a reactive fluid was injected into undergrounds. We performed a visual dissolution experiment on NaCl crystals to simulate the coupling of reaction and dissolution in natural environments. Three typical dissolution patterns including face dissolution, wormholes and uniform dissolution were observed. However, the theoretical foundation...
Root exudates stimulate microbial activity and functions as binding and adhesive agent that increases aggregate stability in the rhizosphere. The exudates produced from plant roots and microorganisms in rhizosphere plays a significant role in the formation of rhizosheath. A high viscosity stabilizes soil aggregates in the surrounding of the root and creates rhizosheath. The formation and...
This talk will present a 3D, continuum-level damage model for simulating Lithium diffusion within generated Li$_x$Ni$_{0.5}$Mn$_{0.3}$Co$_{0.2}$ (NMC 532) secondary cathode particles. The primary motivation of the particle-level model is to inform cathode-particle design and determine charging profiles that reduce cathode fracture. The model considers NMC 532 secondary particles containing...
Metal-Organic Framework (MOFs) are functional crystalline porous material having an open metal site with organic linkers with a wide range of applications. Fundamental properties include a large surface area, the high degree of crystallinity. It is also known that MOFs are of low density and show high thermal stability. Their usage in gas hydrate field is unknown and has not been investigated...
Hydrogen for clean energy is in the national and international spotlight. Offshore wind presents an extensive renewable energy source in the UK, and a large green hydrogen resource, positioning the UK to be a major player in the emerging global hydrogen market. In the UK and around the globe there’s a handful of likely subsurface hydrogen storage sites and it is widely recognised that hydrogen...
Coal beds are dual permeability systems characterized by a porous matrix enclosed within sets of orthogonal fractures known as cleats. Production of coalbed methane (CBM) consists of desorbing methane from the low permeable coal matrix to the high permeable cleat system. Unlike in conventional reservoir exploitation, sorption mechanisms cause shrinkage and swelling of the matrix which...
Studies of colloid transport during transient flow in variably saturated porous media are important to determine the roles of dominant processes on particle remobilization. The main objective of this study is to develop a model to describe transport, adsorption, and release of colloids during cycles of drainage and imbibition under various saturation conditions. For this purpose, two different...
Gravity-driven infiltration of fluids into heterogeneous soil controls the distribution of water in soil and the fate and transport of pollutants through the vadose zone. Infiltration into dry soil is hydrodynamically unstable, leading to preferential flow through narrow wet regions. These preferential channels concentrate water and solute fluxes and persist over cycles of wetting and...
Swimming microorganisms are often encountered in confined, porous geometries where also an external flow is present, e.g. in filters or inside the human body. To investigate the interplay between microswimmer motility, confinement and external flows, we developed a model for swimming bacteria based on point coupling to an underlying lattice Boltzmann fluid. With this implementation, straight...
Bacteria are ubiquitous in our daily life, frequently as surface-attached biofilm communities. In some cases, biofilms serve a positive purpose, such as improving health or remediating polluted water; in other cases, they negatively impact our lives, such as by causing infection or fouling equipment. For both positive and negative purposes, understanding the factors that regulate the onset of...
Hydrogels hold promise in agriculture as reservoirs of water in dry soil, potentially alleviating the burden of irrigation. However, confinement in soil can markedly reduce the ability of hydrogels to absorb water and swell, limiting their widespread adoption. Unfortunately, the underlying reason remains unknown. Here, we report the first direct visualization of hydrogel swelling within a...
Reducing the carbon footprint and the commitment to achieve net-zero targets will be the drivers of global environmental and energy policies in the years to come. Clean energy sources could soon become the premium choice for power generation and transportation. Hydrogen is an important clean and promising alternate energy option that is growing rapidly. Blue hydrogen is made from natural gas...
Wind erosion is an ecological and environmental issue of global concern, with many adverse effects such as damage to infrastructure, economic loss, increased regional poverty, and social instability [1, 2]. Desertification directly caused by wind erosion affects 32% of the world’s population, 67% of countries, and 40% of the land area, making it a serious threat [3]. The United Nations...
A new numerical approach is proposed for the simulation of coupled three-dimensional and one-dimensional elliptic equations (3D-1D coupling). Possible applications are the interaction of a capillary network with the surrounding tissue, of tree roots with the soil, or of a system of wells with a reservoir in geological applications. In all of these cases, in which nearly 1D fractures are...
Chronopotentiometry is a powerful technique to investigate transport phenomena in charged porous medium-electrolyte interfaces, especially those associated with ion transport in the overlimiting regime. It allows to determine the transition time, which is an important characteristic of transient ion transport. Under certain conditions, the Sand equation can be applied to analyse fouling...
Fluid flow in fractured porous media is a common phenomenon in many engineering applications, and many numerical methods have been proposed to capture these processes. Here, a new discrete fracture model based on phase field method is presented. The common discrete fracture models represent fractures by sharp topology in an explicit way, regardless of using conforming or non-conforming mesh....
The simulation of flow and transport in poro-fractured media is a complex task, in particular from the point of view of mesh generation. Indeed, constructing good quality meshes that are conforming to the fractures internal to a rock matrix can be computationally expensive when the mesh has to be simplicial, as for standard Finite Element Methods.
In this talk we introduce novel strategies...
Abstract
An investigation of drug release from granules linking structure, process and release performance
Faraj Shmam, Rachel Smith, Kate Pitt
Particle Technology Group, Department of Chemical and Biological Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, UK
Granulation is a particle enlargement process where coarse or fine particles are agglomerated into large...
The Virtual Element Method (VEM), firstly introduced in [1], is a very recent extension of the Finite Element Method that allows the resolution of partial differential equations using general polygonal grids. This brings forth several advantages including better domain meshing and approximation of geometric features that are of great relevance in tackling problems characterized by complex...
During cycling, volumetric changes of the active material induce stresses on the micro- and macro-scale, leading to cracks and delamination, and deformation of the inactive layers and the casing [1]. The altered microstructure is said to “age” and it suffers from capacity loss and damaging effects like lithium-plating [2]. The quantitative simulation of this battery aging on a microstructural...
Oil and gas deposits are still the largest energy sources among all over the world. The most common and reliable method of their prospecting and exploration is the seismic survey process. It is based on the propagation of seismic waves in geological media and their interaction with heterogeneities (reflection, diffraction, attenuation). Recently, a lot of migration and inversion algorithms...
Gas shales are partially water saturated with their pore space simultaneously filled with brine and liquid and/or gas hydrocarbons. Changes in water saturation can cause swelling or shrinkage, which is of significant importance to natural gas production from unconventional shale reservoirs and sample handling in the laboratory [1]. During hydraulic fracturing, a substantial amount of injected...
Different techniques were used for water shut off and conformance control in the mature oil fields whose sole purpose is to cut the water production and sweep the oil towards the producing wells. Many different types of gel systems were developed for the conformance control but all of them have the risk associated with them. It is common for the gel systems to not only block the water...
We report experiments in which hydrogels equilibrated with carbon dioxide at elevated pressure experience sudden decompression. The hydrogels remain stable until disturbed by a small impact, which initiates the formation of penny-shaped cracks within the hydrogel. The main radius of these oblate ellipsoids grows linearly in time with a growth rate of the order of 1 cm/minute.
Our quantitative...
Polymer electrolyte membrane (PEM) fuel cells are expected to play an integral role as low-emission energy converters in a future energy economy. Although technological maturity of these cells has been demonstrated, the challenge remains to achieve high power performance at drastically reduced platinum loading. So far, the attempts to reduce the platinum loading have been thwarted by severe...
A central component of the rhizosphere is root mucilage, a hydrogel exuded by plants that dramatically alters chemical and physical properties of the soil. It is characterized by its large water holding capacity and is hydrophilic or hydrophobic depending on its hydration status: when swollen, mucilage is hydrophilic but becomes hydrophobic when dry, forming local hydrophobic spots on the...
Assessing the land use and land cover change is crucial for sustainable natural resource management and understanding the changes in hydrologic processes and water cycle. In this study, we aim to quantify the land use and land cover changes in Gilan province of Iran between 1975 to 2015 using Landsat 2 MSS and Landsat 8 OLI/TIRS images, with spatial resolution of 80 m and 30 m, respectively....
In the process of fractured reservoir development, fracture opening pressure, opening sequence, and reservoir fracture pressure are the factors that must be considered when formulating oil and gas development plans. Particularly in fracturing, refracturing, and water injection development measures for a low-permeability reservoir, accurate prediction of structural fracture development law and...
The deformation of fruit tissue caused by drying typically results in consequent quality loss. To better understand the mechanism of heat and moisture transfer, a coupled thermo-hydro-mechanical model was developed at microscopic cell scale. Pear was chosen as the research object as this fruit suffers from great shrinkage after drying. A 2D geometric model of cortex tissue was obtained by a...
Background: Coalbed methane (CBM) is an important natural gas resource of growing interest [1,2]. The injection of CO2 can enhance CBM recovery, meanwhile, CO2 can be stored in the coalbed layer. However, CO2 may induce coal matrix swelling, and an inappropriate injection design may result in the cleat closure of the coal system [3,4]. On the other hand, N2 was effective to promote CH4...
Thermoporoelasticity problem has many applications in science and engineering: geothermal energy systems, nuclear waste disposal, wellbore stability analysis, and others. However, most of the applied problems of thermoporoelasticity cannot be solved analytically. Therefore, it is essential to develop mathematical models and efficient numerical methods. The mathematical model is described by a...
Raising crop production and at the same time reducing environmental spreading of agrochemicals are two current priorities in agriculture. Balancing these needs a quantitative understanding is needed of infiltration phenomena and agrochemical leaching into the subsoil. To this aim, field studies are undoubtedly the most reliable approach to retrieve representative data. Lysimeters are specific...
Gaseous matter exchanges in soil are determined by the connectivity of the pore system which is easily clogged by fresh root exudates. However, it remains unclear how a hydrogel (e.g. mucilage) affects soil pore tortuosity when drying. The aim of this study is to obtain a better understanding of gas diffusion processes in the rhizosphere by explaining patterns formed by drying mucilage.
We...
Compared to bulk soil, the rhizosphere has different properties because of the existence of root mucilage which affects the physical, chemical, and also microbial processes. Hydraulic phenomena like limiting water flow at certain dry soil conditions, modulating extreme water contents by slow response to water potential changes; and also influencing solute transport and gas diffusion by varying...
Understanding deformation and fluid flow in a fractured rock mass is of central importance for geothermal energy extraction, wastewater disposal, and hydrocarbon exploration. Thermal strain- or fluid pressure - induced shear displacements in the fracture system lead to hydraulic aperture changes that affect the flow field. To predict these, numerical frameworks are needed that can accurately...
The fate and transport of agrochemicals in soils have important implications for groundwater quality and public health. Land management practices deliberately change the pore structure, which consequently controls how mass is transported through the subsurface of agricultural lands. This study employs direct numerical simulations (DNS) to investigate the differences in transport behavior in...
Low salinity waterflooding (LSW) attracts increasingly attentions in recent years. It has been proposed that the enhanced oil recovery by LSW (or low salinity response) is triggered by the electrochemical interactions (e.g., electrostatic interactions, multiple ion exchange, chemisorption, etc.) between brine, rock, and oil. This study used the methodology of surface complexation modeling to...
Agrochemicals and fertilizers are central to modern agriculture and are credited with the large increase of crop yield as part of the Green Revolution of the 1960’s. Timely and targeted fertilizer application is an important component for reducing costs and minimizing unintended release to the environment and water resource pollution. The efficiency of highly mobile fertilizers (i.e., nitrate)...
The transformation of the liquid menisci at pore throats is of great importance for mitigating the liquid-blocking effect of condensate reservoirs. Here, we reported a super gas-wetting peanut-like nanoparticle which can facilitate the liquid menisci to transform from concave-shape to convex-shape by coating a super gas-wetting adsorption with high surface roughness. The morphology and surface...
Integrating renewable energy technologies into the grid is necessary to enable a sustainable energy economy but is currently challenged by their intrinsic intermittency. Redox flow batteries (RFBs) are rechargeable electrochemical reactors that are promising for grid-level energy storage due to their ability to decouple energy and power. However, current RFB systems remain too costly for...
Preferential flow-paths are well-known features in fractured rock masses, often allowing rapid movement of fluid and early breakthrough of solutes and/or heat/cold in a small fraction of void space, compared to non-fracture-dominated porous media. These preferential flow-paths can change as the configuration of fractures varies, due to, for example, shear displacement (Yeo et al.,1998; Kluge...
Reactive transport in porous media is a dynamic field of research with open questions particularly at pore-scale. Despite our detailed understanding of non-reactive multiphase flow in porous media, across scales, little is known about the pore-scale dynamics of processes involving chemical reactions alongside fluid flow in porous media. Reactive flow plays a key role in a rage of application...
Fluids involved in activities occurring in fractured underground reservoirs, either related to natural resource recovery (e.g., hydrofracturing, drilling, geothermal exploitation) or environmental remediation schemes, often exhibit complex rheology. The micro-structure of foams, muds, emulsions, or colloidal suspensions induces shear-thinning in the continuum scale mechanical behaviour, which...
This paper investigates the spatial patterns of metal deposit on battery cathode by electrodeposition during use. This is done by modelling with a reaction-diffusion system on a finite two-dimensional domain and examining the conditions required for Turing instability. Turing instability requires analysing the stability of the system allowing for diffusion and also without diffusion. Phase...
With the development of large quantities of gas injection in shale and tight reservoirs, the multiphase behavior in nanoscale pores before and after gas injection has gradually attracted people's attention. A large number of published literature have shown that due to wall adsorption and capillary force, the phase behavior of confined fluid in micro and nano pores is significantly different...
Polymer flooding is an enhanced oil recovery technique applied to reduce mobility ratio and improve sweep efficiency [7]. In addition, polymer solutions can be used as relative permeability modifiers (RPM) in order to increase the recovery factor due to flow diversion [1]. In the applications mentioned above, high viscosity and polymer retention (mechanical retention and adsorption) may cause...
Viscous fingering commonly takes place when a low viscosity fluid displaces a higher viscosity fluid. Although the fundamental principles governing the interfacial pattern in Hele-Shaw cell are well understood, their manifestation in porous media remains elusive. Here, we study viscous fingering in hierarchal porous media (HPM) consisting of a spatially-organized bimodal pore size...
The thermal energy distribution of the Yellowstone terrestrial hydrothermal system is driven by a mantle-derived magmatic plume which has both Iron-Magnesium rich and Aluminum-Silicate rich phases and supplies thermal energy to the surface (Crough, 1978). The Yellowstone hydrothermal system is in steady-state within neighborhood of geologic time (10's Ka) and steady-state diffusive nature...
Solute transport plays an important role in many soft porous materials, including the movement of contaminants in soils and the movement of nutrients and waste in living tissues and tissue-engineering scaffolds. These systems are also often exposed to large, periodic loading and deformation, which drives nontrivial fluid motion and changes in pore structure. Here, we study the strong coupling...
Cellulose has a very large range of applications in many aspects, and the drying of cellulose are widely adopted in many industrial processes. The deformable property of cellulose fibers, along with water adsorption capacity, add complexity to its drying mechanisms. In this work, we study the global mass loss and the spatial evolution of the internal water content of cellulose during its...
We model the displacement of oil from idealized porous media by simulating the quasi-static injection of gas into oil-filled channels with uniform cross-section under different wetting conditions.
We consider channels with triangular or rectangular cross-section that are initially filled with a single fluid (e.g. oil). A second, displacing, fluid (e.g. gas) is introduced at one end of the...
Rayleigh-Taylor (RT) convection is a buoyancy-driven instability arising when a denser fluid overlies a less dense one in a gravitational field. In this work, we study RT instability in porous media where the denser fluid on the top is also more viscous. We perform high-resolution numerical simulations through hybridization of pseudo-spectral and compact finite difference methods. Using our...
Darcy’s Law, an important equation relating flow velocity in a porous medium to the permeability of the medium and the viscosity of the fluid, can be extended to form flow models for petroleum fluids in a reservoir by combining it with a fluid model and conservation of mass. The resulting models are central to reservoir engineering. Analytic solutions to these flow models, developed by Van...
In order to study the efficacy of mineral trapping scenarios for CO$_2$ storage behaviour in deep layers, demanding highly nonlinear coupled diffusion-advection-reaction partial differential equations (PDEs) have to be solved.
The chemistry includes both general kinetic and equilibrium reactions.
Realistic scenarios further ask to simulate the inflow of various gases into the deep...
Archaeological wood of shipwrecks buried for centuries under sea sediments is highly degraded due to the chemical changes and material loss. Uncontrolled or rapid drying of such artifacts results in drastic distortion and collapse of material due to high drying stress, therefore consolidation methods and drying processes have been developed to preserve these culturally valuable artifacts. As a...
Numerous experimental observations and field applications have confirmed that low-salinity water flooding is an effective technique for enhanced oil recovery. Given the complex physical and chemical processes, several controlling mechanisms have been proposed to explain the oil remobilization due to low-salinity effects. Osmosis and water-in-oil emulsification are among these mechanisms....
Stability of foam in the presence of hydrocarbons is a crucial factor in the success of its use in various applications in porous media, such as soil remediation and enhanced oil recovery. (EOR).In this study, we investigate the effect of surfactants with different charges (anionic, cationic, and non-ionic) on foam stability in the presence of charge-stabilized silica (SiO2)...
Among the demanding challenges of the 21st century, clean energy supply is still challenging to the scientific community to mitigate global warming. In this regard, transforming renewable energy into a stable and reliable fuel form by electrochemical methods is a promising technology. The polymer electrolyte membrane (PEM) water electrolysis is a key technology which uses water as feedstock...
Permeability is a parameter introduced by Darcy’s Law, which is believed to be an intrinsic property of the porous medium and should be independent of the nature of the fluid flowing through it. However, Darcy’s Law has specific conditions. The assumptions inherent to Darcy's law are (1) a single, incompressible fluid is flowing; (2) flow is in the laminar regime; (3) the fluid is immobile at...
Porous electrodes are an essential component of Vanadium Redox Flow Batteries (VRFBs), which are one of the most promising technologies among the energy storage systems required for the integration of the growing supply of renewable energies into the electric grid. Vanadium RFBs have been engineered for decades and currently exhibit some early commercial scale implementations. In this context,...
Gas hydrates are ubiquitous in seabed and submarine rocks in continental slopes around the world. Formation and dissociation of hydrates in porous spaces can alter the geomechanical strength of hydrate-bearing rocks. Dissociation of hydrates in submarine slopes decreases the elastic moduli and cohesion of rocks and can trigger slope failure. Failure of submarine slopes can cause damage to...
Due to recent advances in imaging technology, calculating the macroscopic properties of a porous medium through pore-scale simulation has become very common. There are several methods to simulate pore scale flow patterns [1], [2]. Among those, lattice Boltzmann method (LBM) has been widely used by scientists because of its simple approach in modeling the complex pore space boundaries, a key...
Predicting the induced change of fluid pressure in an unsaturated porous medium during undrained loading/unloading processes is challenging because two different fluids (a liquid and a gaseous solution) and a mixture of solid particles are involved. The relative presence of the two fluids and solid particles in the medium of interest, their stiffness, and the initial conditions in terms of...
Nonlinear oil flow through porous media near a sealing fault has a key role in reservoir engineering because the existence of sealed zones in many types of reservoir rocks present in the world. This work proposes a new unsteady 2-D permeability pore pressure-dependent model for a wellbore near a sealing fault, where analytical solution is based on an integro-differential solution of the...
Understanding mineral reaction rates in porous material is crucial in many environmental systems such as natural weathering process, enhanced oil recovery, radioactive waste disposal etc. Prediction of in-situ mineral reaction rates is challenging, and a significant variation is observed between laboratory data compared to field data due to factors like variation in the physicochemical...
This work aims to understand the relationship between the spatial flow distribution and its underlying pore structure in heterogeneous porous media. Thousands of two-dimensional samples of polydispersed granular media are used to 1) obtain the velocity field via direct numerical simulations, and 2) conceptualize the pore-network as a graph in each sample. Analysis of the flow field allows us...
Producing energy from intermittent renewable energy sources has been developed over the past decades. One of the goals at the grid-scale is to provide sustainable energy output to the end-users [1]. To this end, efforts must be done to store a huge amount of energy in robust batteries to provide stable and flexible electricity to the customers during peak hours. Redox flow batteries (RFBs)...
The process of indentation by a rigid tool has been widely studied for its versatility as an experimental technique to probe constitutive properties of materials of various kinds across multiple scales. Recently the technique has been applied to characterize poroelasticity of soft materials such as polymeric gels via load relaxation experiments, where an indenter is pressed instantaneously to...
In this work we present open-source solvers, based on the finite volume library OpenFOAM, for solving the Stokes-Poisson-Nernst-Planck (SPNP) system of equations for single or multi-domain ionic transfer. Many applications that involve said ionic transport, e.g reinforced concrete [1], batteries [3] and oil extraction [2], also involve heterogeneous reactions between domains. As such,...
Geomechanical deformation can alter the flow field which impacts solute mass fluxes. Despite its importance, the effects of the coupling between geomechanical deformation and the flow field on solute transport behavior are not fully known. In this work, we study the impact of this coupling on the solute concentration distribution. The concentration field is semi-analytically derived by making...
We consider a mathematical model for two-phase immiscible flow in a porous medium. A solute is present in and transported by one fluid phase, leading to a non-constant surface tension. At the scale of pores, the main challenge is to account for the movement of the fluid-fluid interfaces, depending on the velocities and pressures of the two fluids, and on the concentration-dependent surface...
We present a new concept for modelling single-phase flow and energy transport in porous media including conditions under which local thermal equilibrium cannot be assumed. A dual network model is introduced based on a recently developed algorithm to represent both the pore space and the solid grain matrix in a porous medium by interconnected networks.
Heat and mass transfer are considered...
Wetting films can develop in the corners of pores in porous media under strong wetting conditions where the contact angle allows the wetting phase to invade the corner. Such corner flow has a significant influence on the two-phase flow dynamics. Compared with the main meniscus rising within a pore, the wetting corner film is much thinner and can lie significantly ahead. Modeling the dynamics...
The modelling of multiphase flow and mechanical response in fractured chalk formations due to oil and gas explotation is of major importance in the understanding of the subsurface processes and the environmental impact associated with such activities. In addition, this knowledge is highly essential to predict unwanted effects from future carbon capture and storage (CCS) practices [1-3] and...
This study proposes and demonstrates a new pore-network modeling approach to simulate single-phase reactive transport and mineral dissolution in porous media. A new algorithm for the merging of pores and throats resulting from solid dissolution is introduced to guarantee the conservation of the main variables of interest during the merging process. Pore surface areas and throat conductances...
Anthropogenic and natural fractured aquifers are common examples of dual porosity matrix-fracture systems, where the fracture network provides highly-conductive flow pathways and the low-permeability matrix stores most of the fluid. Fluid production or extraction leads to land subsidence and potentially to induced seismicity. Mechanical deformations have recently been proposed as effective...
Several techniques which are widely employed for the estimation of hydraulic parameters of aquifer systems are based on particle-size and porosity information. These rely on empirical formulations which are usually adopted to obtain hydraulic conductivity from quantiles of particle size curves and porosity. We present analytical formulations relating the spatial covariance of the (natural)...
Numerous green technologies are based on heat and mass transfer in porous media at high temperatures : heat exchangers for thermodynamic solar power plants, biofuel production from biomass, etc.
This type of transfer often involves several non-Darcian effects such as inertial [1], compressibility and unsteadiness effects, and, most importantly, local thermal non-equilibrium effects between...
On the fluid-rock interface, the order of the molecular structure and dynamical properties of fluid deviates from that of the bulk phase and the fluid exhibits a different thermodynamic behavior. To develop an understanding of the fluid-rock interface molecular dynamic (MD) simulation is conducted for water-calcite system. In this study, the results of MD simulations explicitly exhibit the...
When two immiscible fluids flow in a porous media at rates where the capillary and viscous forces compete, there is growing experimental,
numerical and theoretical evidence that the flow rate depends on the pressure gradient minus a threshold pressure to a power between 1.5 to 2
[1]. At higher flow rates, where viscous forces dominate, the flow rate becomes proportional to the pressure...
please see attachment
Advances in technology and computational power have led to an increased impact of digital rock physics, i.e., simulations on the rock’s pore space obtained from computer tomographic imaging. Various processes can be simulated either directly on the obtained structure or on abstracted networks in order to obtain rock and fluid properties such as relative permeability and capillary pressure...
The integration of horizontal well drilling and hydraulic fracturing has improved oil production from tight oil reservoirs. The oil recovery potential using primary recovery is cumbersome due to its robust tight formation; thus, the remaining oil in place in the tight oil reservoir required an effective method to improve the oil recovery from the tight oil reservoir. The implementation of...
We are concerned with a Bayesian framework for rock characterization consisting of a
preconditioned Markov chain Monte Carlo (MCMC) method in conjunction with a
truncated KL [1] expansion for the parametrization of the underlying uncertainty in
subsurface properties [2]. Reduction of the overall uncertainty in determining reservoir
characteristics can be achieved through the incorporation...
We consider Blunt’s [1] pore as a straight cylindrical conduit of a triangular cross-section OO1O2. A viscous liquid bridge is bounded by menisci AMD and CNB which are assumed to be circular arcs of radii, r1 and r2, only slightly varying in the f-direction perpendicular to Fig.1a.
Fig.1
The contact angle /2. Flow in the f-direction (Fig.1b) is caused by the longitudinal gradient of...
Drying of porous media sounds simple yet it is complicated to understand the physics behind it. As drying is an energy-intensive process, it is necessary to understand the trade-off between energy costs and efficient drying process using recently developed mathematical models. In our previous presentations [1]–[3], we addressed a novel isothermal diffusion dominated drying model using the...
The shale oil reservoir of the Lucaogou Formation in Jimusaer Depression, Xinjiang Province, China, features a structure exhibiting several issues, such as complex lithology, and an ambiguous pore-throat structure and configuration. To resolve these issues, numerous contemporary experimental methods, including focused ion beam scanning electron microscopy (FIB-SEM), nano-scale CT scanning...
An electromagnetic (EM) heat exchanger (HX) converts EM energy into heat or useful mechanical work. Examples of EM HXs are microwave thermal thrusters where high-power microwave heating is utilized to produce thrust from compressed gases, solar-thermal panels where a fluid is heated through solar radiations, etc. Our research is focused on modeling an EM HX useful in wireless power beaming...
New developments in carbon capture and storage (CCS) technology are under constant demand, and current initiatives focus on evaluating the possibility to store carbon dioxide (CO2)below the seabed in the North Sea [1]. The Draupne Formation is a promising candidate and acts as a caprock for deeper reservoirs [2]. Injection of CO2 in such formations could cause changes in the in-situ stresses,...
A three dimensional parallel implementation of Multiscale Mixed Methods based on non-overlapping domain decomposition is proposed and its computational performance is assessed by means of numerical experiments. As a prototypical method the Multiscale Robin Coupled Method [1] is chosen and its implementation is explained in detail. Numerical results for problems ranging from millions up to more...
Abstract
Permeability and its distribution play a major role in productive capacity of petroleum reservoirs and hence its prediction is crucial in predicting reservoir performance and determining well production rates. In recent years, the technology of digital rock physics has been introduced as a powerful tool to compute the petrophysical properties of porous materials based on 3D...
The capillary pressure defined as the pressure difference between the non-wetting and wetting fluid is one of the important parameters that govern the multiphase flow through porous media. Traditionally, the capillary pressure-saturation relationship is determined under equilibrium conditions. However, it has been demonstrated in previous studies, that the dynamic conditions of the system (i.e...
It is reported that approximately only one-third of the original oil in place can be economically recovered from the reservoir after primary and secondary recovery (Osei-Bonsu et al., 2015, p. 520). Miscible gas flooding and steam gas injection, as effective enhanced oil recovery (EOR) techniques, suffer from poor sweep efficiency due to reservoir heterogeneity, gas fingering and gravity...
Currently, more than 30 Gt of anthropogenic CO2 is emitted per year, mainly from combustions of fossil fuels. The emissions of CO2 into the atmosphere play an important role in global warming and lead to key environmental problems. Interestingly, enhanced oil recovery (EOR) methods have been employed for CO2 storage and improving oil recovery. For example, in 2019, CO2-EOR delivered about 2.5%...
Gravity currents are primarily horizontal flows driven by a density contrast between the current and the ambient fluid. Viscous gravity currents propagate under a viscous-buoyancy balance, inertial forces being negligible except at the very beginning of motion. Non-Newtonian currents arise in several environmental and industrial applications when the fluid has a nonlinear stress-strain...
Abstract
Moon base in the not-too-distant future has been brought to the table and the abundant lunar regolith can be used for construction materials. Due to lack of water in the moon, sintering methods (e.g., solar, vacuum and microwave), are considered to manufacture lunar regolith blocks with expected strength. Microwave sintering experiments has been conducted in our laboratory using...
Multiphase flow in porous rocks plays a key role in CO2 sequestration, groundwater remediation and petroleum reservoir management. In the subsurface, drainage and imbibition typically take place at low capillary numbers, meaning capillary forces dominate the pore scale behavior. The fluid displacement is then strongly influenced by the wetting properties of the pore walls, which is typically...
Hydro-soluble polymer solutions are used in porous media for a range of applications from, enhanced oil recovery, ground water remediation and as permeability modifiers in oil reservoirs. During flow of these polymer solutions in porous media, shear viscosity dominates at low and intermediate shear rates, with the polymer solution undergoing a transition from Newtonian to shear-thinning...
Wettability and wettability alteration plays a vital role in many applications to understand the hydraulic conductivity and quantify many Darcy scale flow parameters during multiphase flow in a porous medium. The wettability influences the fluid-solid and fluid-fluid interfacial areas. Ideally, the fluid-solid interfacial area in a porous medium for a non-wetting fluid can be zero when thin...
The interaction of viscous and interfacial flows with soft materials has recently attracted substantial interest from a variety of different perspectives. Here, we study these interactions in the context of a model problem: Flow in a deformable Hele-Shaw cell, where one wall is rigid and the other is soft. Combining experiments with mathematical modelling, we consider the coupling of flow and...
Most natural porous media have a rather complex structure. Usually the solute transport in a porous medium is described within the framework of the standard diffusion model [1]. However, many experimental data [2, 3] cannot be explained into frameworks of such approach, because the transport through a porous medium is often complicated by the immobilization of solute. The immobilization leads...
Understanding the physics of immiscible two-phase flow in porous media is not a straightforward process due to the large number of influencing factors. Such factors are, among others, the inherent fluid properties, the solid-fluid interactions, the properties of the solid structure, and the boundary as well as the initial conditions. Since two-phase flow has a significant impact on many...
In carbonate reservoir rocks, the pore system can be vary significantly with variations in the rock component texture and distribution as viewed at different length scales. Any textural variability is reflected in the associated permeability tensor and makes the evaluation of the hydraulic behaviour of this group of rocks very challenging. In this study, we investigated the impact of the...
Carbon capture and geologic storage, mainly in deep saline aquifers, is extensively considered as an essential component of any strategy to achieve carbon neutrality and effectively mitigate climate change. At pressure and temperature conditions relevant to CO2 storage in sedimentary formations, CO2 is less dense than the resident brine and tends to float, threatening the long-term storage...
The macroscopic mechanical behaviour of granular-porous media is largely influenced by kinematics of its micro-mechanical counterparts of particles and pores. Deformation at particle-level is not uniform across a granular sample but is localized along the directional force chain, thus forming shear intensive failure surface known as shear zone. This results in complex internal failure mode and...
ScCO2 was used as the solvent and intercalator when micro crystalized Ca-montmorillonite(MC Ca-MMT) was modified from Ca-MMT powder. With micro crystallization, carbonates crystallite was produced between Ca-MMT layers and provided active sites for the further reaction when mixed with oilwell cement. Enhanced oilwell cement by MC Ca-MMT was investigated based on the mechanical property and...
Water-alternated-emulsion (WAE) injection is an alternative chemical enhanced oil recovery method (cEOR) that improves water mobility control and sweep efficiency flow diversion. When injected, the dispersed phase of stable diluted oil-in-water (O/W) emulsions flow as conformance agents towards the thief or high permeable porous media zones blocking the preferential flow paths by different...
Investigation of multi-phase flow in heterogeneous porous media is important for several fields, including enhanced oil recovery, CO2 storage in geological formations, and groundwater contaminant treatment. One of the key properties in characterizing such flows is phase permeability and its dependence on saturation, i.e. relative permeability curves. Such properties are usually determined via...
Accurate representation of the pore space is of utmost importance in the modeling of flow and transport in porous media. The challenge arises in heterogeneous rocks particularly with wide pore size distributions where the ratio of smaller pores to the sample size is very small. This is obvious, for instance, in the pore-level images of most carbonates where there is a trade-off between...
In contrast to water (as a Newtonian fluid), the flow of some non-Newtonian fluids through porous media is related to the geometry of the pores in a way that allows to backtrack some information, such as the approximate distribution of the effective pore sizes. This can be (and has been) done in various ways, cf. the yield stress fluid porosimetry method (YSM), based on the yield stress fluid...
Over the last decade multiple studies have shown the significance of controlled salinity water-flooding (CSW) as an efficient technique to improve recovery from oil fields. Most of the published experimental work in the literature was performed at the core scale and mainly focused on comparing the incremental oil recovery from low salinity (LS) and high salinity (HS) brine injection in...
With the advent of paper microfluidics and the concept of Point-of-care healthcare diagnostics, study of imbibition of complex fluids in porous media has become significantly important. In these applications, a rapid and even spread of complex fluids on absorbent paper is essential to ensure a uniform component spread for accurate chemical and bio-sensing. Especially in the case of blood...
In this study, reaction experiments between CO2-saturated brine and wellbore cement samples cured under different pressures were conducted to study microstructural and mineral composition changes using micro-computed tomography (micro-CT), scanning electron microscopy (SEM), digital microscope (DM) and Raman spectroscopy. The CT images of post-CO2 exposure cement samples showed a...
Understanding emulsions' behaviour is essential for many industrial applications such as environmental remediation, Enhanced Oil Recovery (EOR), and food processing. Although several experimental studies have been previously performed to study emulsion behaviour, fewer of them have specifically addressed the correlation between emulsion behaviour in bulk-scale to pore-scale. Firstly, we tried...
Surfactant flooding has considered to be one of the most useful approach to recovery residual oil that trapped in pore space after waterflooding. From a macroscopic perspective, this is the surfactant molecules – that are adsorbed on the oil/water interface – would significantly reduce the interfacial tension (IFT) and thus result in the change of wettability in the oil-water reservoir...
Threshold pressure (or capillary entry pressure) is the minimum pressure difference required for the non-wetting fluid to penetrate a capillary filled with a wetting fluid. It is well known that this capillary pressure for the circular capillary can be calculated by Young-Laplace equation. While for capillaries with irregular sections, the MS-P method, which was originally proposed by Mayer...
Water acts as a very important agent in salt and frost weathering responsible for major physical damage to both natural rocks and building stones, and compared to the idealised laboratory research, distinctly fewer field studies investigated water’s role in weathering processes on natural rock exposures. Especially, there is a lack of knowledge about the critical interaction between soil and...
Fluid-fluid displacements with adverse viscosity ratios are prone to instability, and their interaction with underlying heterogeneity in a porous medium can cause a variety of fingering structures to emerge. The transient dynamics of these processes are both hard to capture experimentally, and difficult to model numerically, leading to conflicting studies with differing mechanisms for their...
Turbulent natural convection in porous media has received increasing attention in recent years, especially due to its significance in emerging engineering applications, such as the long-term storage of CO$_2$ in deep saline aquifers or thermal-energy storage systems. Macroscopic equations are usually solved to calculate natural convection in porous media. The numerical solution of...
Analyzing interfacial phenomena like Viscous Fingering instability happening between two miscible fluids in a porous domain brings advantages in various areas, comprising of chemical and petroleum engineering, environmental engineering, and medicine. Viscous fingering (or Saffman-Taylor) instability (VFI) arises when a low-viscosity fluid is injected to displace a high-viscosity one. From a...
Hydrographical systems which are mainly comprised of dams, rivers, channels, etc. are in the category of large-scale networks. These systems are not only complex systems in case of consisting of different hydraulic devices such as pumps or gates, but also they are in exposure to complicated circumstances like different demands, unknown inputs, drought periods, rainfall, and floods. Thus for...
Block copolymer ultrafiltration membranes have a wide range of applications from drug delivery to water purification and virus filtration. Although optimizing flow is critical to the performance of such ultrafiltration membranes, little success has been reported on their numerical flow characterization. The main challenges have been reported as i) hierarchical pore structure delineation and...
We present an efficient computational approach for simulating component transport within single-phase free flow over a soil. A numerical model based on this approach was validated using controlled experiments in a climate-controlled low-speed wind tunnel. The wind tunnel is interfaced with a soil tank to study problems of heat and mass flux across the land-atmospheric interface....
Vugs are very common presence in carbonate rocks. According to vugs interconnection, vuggy pore space can be divided into separate-vugs porosity system and toughing-vugs porosity system. Separate-vugs porosity system is also the target rocks for acidizing, in which the addition of vugs only increases the total porosity but has no significant increase of permeability. But few works have been...
In a variety of technical, medical and environmental applications, free flow coupled to porous-medium flow plays a crucial role. Due to the strong mutual interaction of the flow in both regimes, complex flow fields develop in the free-flow regime [1]. This holds especially true in the case of rough porous-medium-free-flow interfaces or when pores of a pore-network [2] touch the freeflow. Those...
Since the parametric and predictive uncertainty are inherently inevitable in subsurface flow modeling, various data assimilation methods have been increasingly implemented to constrain the numerical models over the past decade. For example, the Bayes-based ensemble Kalman Filter (EnKF) has been efficaciously applied to updating model pressure state together with hydraulic conductivity by...
Research on the thermal-hydraulic-mechanical (THM) coupling effect in porous media from the perspective of pore-scale is of great significance for the study of enhanced oil recovery, nuclear storage and geological sequestration of CO2. The flow of multiphase fluid in porous media is affected by the thermal-hydraulic-mechanical coupling effect, and the interaction of multiple fields brings...
The numerical simulations of the gas hydrate reservoir are used to predict the reservoir response during the production tests. The complexity of the gas hydrate reservoir needs to be carefully studied through the reservoir simulations to model the long-term production tests. The feasibility of the gas production has already been demonstrated from the short-term production tests. However, the...
Membrane filtration with a feed containing multiple species of particles is common in the industrial setting and many experimental results are available; however, little theoretical work in terms of first-principles mathematical modeling has been reported. We propose a simplified model for filtration of a suspension containing an arbitrary number of particle species, each with different...
Flow and multi-component reactive transport in unsaturated/saturated porous media are modeled by ensembles of computational particles moving on regular lattices according to specific random walk rules. The occupation number of the lattice sites is updated with a global random walk (GRW) procedure which simulates the evolution of the ensemble with computational costs comparable to those for a...
The imbibition mechanism is the basis for efficient development of unconventional dense reservoirs，and it is the key to clarify the imbibition mechanism to find out the driving forces of oil imbibition in porous media. Based on MRI and static permeation test, the In-situ changing images of oil in different cores from ultralow permeability to high permeability were obtained for 200h days. These...
In this work we derive a higher-order numerical scheme for the single-phase multicomponent flow in porous media. The mathematical model consists of Darcy velocity, transport equations for components of a mixture, pressure equation and supplemental constitutive relations. The combination of higher-order discontinuous Galerkin method for the discretization of transport equations and higher-order...
StoSAG is an important method to solve optimization problems in reservoir management. But it also faces a major problem-falling down in local optima. We propose some improvements of StoSAG. First, we study the effect of the ensemble number, the cut step number, the initial ensemble, and the initial step size on final optimization value. The performance of the StoSAG is tested on 48 common...
In electrochemical synthesis processes like chlor-alkali electrolysis with oxygen-depolarized-cathodes, porous Gas Diffusion Electrodes (GDE) have to ensure the intimate contact between the silver catalyst, the gaseous reactants and the liquid electrolyte. In the manufacturing process of the electrodes non-wetting Polytetrafluoroethylene (PTFE) is added to change the wettability of this...
We will present our recent results on the development of semi-Lagrangian meshless Lattice Boltzmann method and its application to porous media flows. Our approach for meshless LBM will be similar to [1]. Here however we will operate on non-regular discretizations. Thus, it will be possible to easily refine discretization e.g. in narrow passages of pore-space. Results on velocity fields and...
Conventional digital rocks constructed by micro-CT with single resolution cannot identify entire pore space and mineral components of tight sandstones due to the multi-scale pores and high clay contents. The porosities of digital rocks are far less than those measured in lab, which results in the difference between measured petrophysical properties and calculated properties based on digital...
Direct modelling of multiphase flow in pore structures at the micron-scale and at low capillary number is challenging for two reasons. Firstly, numerical error in the modelling of interface curvature and surface tension force leads to large spikes in velocity called spurious currents. Secondly, accurate and robust modelling of capillary waves requires small time-steps based on the Brackbill...
Non-Archie’s law phenomenon, where the saturation exponent varies with the water saturation, has been observed for tight sandstones due to bimodal pore size distribution and high clay content. In the study, we proposed a new method to analyze pore connectivity by multi-scale imaging techniques and established dual-porosity conductivity model for tight sandstones. Firstly, broad ion beam...
The unsteady nonlinear oil flow in porous media makes hydraulic diffusivity equation (HDE) harder to solve analytically and numerically. This work proposes a porous media formation damage evaluation caused by the permeability decay as function of pore pressure. To evaluate this phenomenon, a new integro-differential analytical model using Green's functions (GF's) is proposed to solve nonlinear...
Safety assessment (SA) studies for spent nuclear fuel repositories in fractured rock entail the need to account for very large spatial and temporal scales. This is typically done by using continuum-based or Discrete Fracture Network (DFN)-based numerical simulations, which in turn rely on upscaled groundwater flow and transport parameters. However, model parameterisation is sometimes based on...
Estimation of subsurface hydraulic parameters is always complicated often due to lack of the available information. For the reliable estimation of the hydraulic parameters i.e. hydraulic conductivity (Ks) and porosity (Ɵs), experiments are conducted at lab scale but for field scale it’s expensive, time consuming and not feasible. The alternative approach is to use empirical relation based on...
Understanding the transport processes in clay rocks such as Opalinus Clay (OPA) is essential for their usage as host rocks for geological disposal of high-level radioactive wastes. The sandy facies of OPA is heterogeneous and anisotropic, comprising intercalated sandy and carbonate-rich layers in the clay rock matrix. The representative elemental volume (REV) analysis can provide an enhanced...
When capillary and viscous forces compete, there is experimental evidence for the flow velocity to depend on the pressure gradient to a power between 1.5 and 2 [1]. Some of these experiments are done with both immiscible fluids being incompressible, and some are done with one of the fluids being compressible and the other being incompressible. On the other hand, the theory that has been...
The microstructures of shale gas reservoirs are significant for the study of gas transport mechanisms and the formulating of the gas exploitation plan. In this work, the composition, scanning electron microscopy images, and adsorption information of Longmaxi shale samples are experimentally obtained. The fractal features of shale microstructures are systematically analyzed based on fractal...
Statistical prediction is often required in reservoir simulation to quantify production uncertainty or assess potential risks. Most existing uncertainty quantification procedures aim to decompose the input random field to independent random variables, and may suffer from the curse of dimensionality if the correlation scale is small compare to the domain size. In this work, we develop and test...
Nowadays, digital rock physics (DRP) has enabled us to obtain comprehensive and accurate information from porous media and a better understanding of physics at the pore scale. Advances in the micro-computed tomography technology (µCT) have led to high-quality, high-resolution images from rock samples. However, this increase in image quality or resolution raises imaging expenditures. Thus, the...
Carbonate rocks are characterized by their complicated and heterogeneous pore structure [1]. In general, mechanical and chemical compaction, cementation, dissolution, mineral transformation and fracturing are among the most important factor typically affecting the fabric of a carbonate rock, and so, its lithofacies and petrophysical properties (e.g. porosity and permeability) [2]. In this...
A correct choice of interface conditions and useful model parameters for coupled free-flow and porous-medium systems is vital for physically consistent modeling and accurate numerical simulations of applications. We consider the Stokes-Darcy problem with different coupling strategies: classical and generalized interface conditions on the sharp fluid-porous interface and the pore-network model....
The individual and combined impact of pore size disorder and wettability on the fluid distribution in different applications including hydrocarbons recovery, underground storage and soil remediation has been widely studied [1,2]. However, the combined effect of heterogeneities in both pore structure and wettability is not fully understood. Wettability plays an important role in multiphase flow...
Immiscible two-phase flow in porous media has drawn great attention in various applications including soil remediation, enhanced oil recovery, and CO2 sequestration ( Zarikos et al., 2018; Alamooti et al., 2020). One of the main effective processes on the performance of these applications is the trapped phase mobilization phenomenon. The balance of total drag forces (including pressure and...
Ageing is a common technique within the oil indurtry research community to mimic the conditions of crude oil reservoire. Thereby, the porous rock is exposed to crude oil at elevated pressures and temperatures. In particular, the wettability conditions estaiblished through this procedure are known to significantly incluence the flow behaviour in porous rocks. In this study ageing of mineral...
Accompanying the great achievements owing to the quick development of science and high technology, the greenhouse effect and energy crisis have shown serious negative impact to human society. Aiming at solving the two problems simultaneously, the CO2 Enhanced Oil Recovery (CO2-EOR) technology has attracted wide research interests. Taking CO2 as the injection fluid, this technology can not only...
Multi-scale structural assessment of biological soft tissue is challenging but essential to gain insight into structure-function relationships of tissues and organs [1-4]. The human placenta is one of the most complex vascular organs of the human body. It is an exchange organ with a large surface area of the feto-maternal interface packed in a relatively small volume. The human placenta has...
Asphaltenes deposition can have a detrimental impact on hydrocarbon recovery efficiency. Therefore, it is imperative to study the fundamental mechanisms controlling the asphaltenes flocculation and deposition in reservoirs. The primary objective of this study is to visualize the deposition of asphaltenes and their subsequent removal by ultrasonication in Indiana Limestone using state of the...
This study integrates mathematical modeling and microfluidic experiments to study the impacts of imaging domain size on determining the permeability of porous media with evolving biofilm ratios. E. coli biofilms were grown to three biofilm ratios: low (2.7%), intermediate (17.6%), and high (55.2%) inside a microfluidic channel packed with a single layer of glass beads. Two-dimensional biofilm...
An overview of the Electrical Impedance Spectroscopy (EIS) method targeting the physical processes specific to the water-based ink/substrate interaction is made in this work. After a brief introduction of the EIS technique , , two experimental setups will be presented as the main EIS measurement instruments: planar and respectively cylindrical electrodes. They have been employed to study...
Nowadays, thin porous media have attracted much attention because of their importance to various industries. Hygiene products, paper, filters, fuel cells, membranes, textiles, muscular tissues, and other biological or manufactured thin compositions are widely encountered in daily life. The typical characteristic of a thin porous layer is that its thickness is much smaller than its in-plane...
The motivation for the present study stems from visualizations of the PTFE distribution in the gas diffusion layer (GDL) of Proton Exchange Membrane Fuel Cell (PEMFC). The GDL is a fibrous carbon layer treated with polytetrafluoroethylene (PTFE), by drying a layer saturated with a solution of PTFE particles, to improve hydrophobicity [1, 2, 3]. During the fabrication, internal surfaces...
Displacement of particle suspension by air is ubiquitous in nature where the particle transport plays an important role in the displacement process. Here we experimentally study the film entrainment and particle transport during gas–suspension displacement in microchannels. We characterize three flow regimes, ranging from no deposition to particle entrapment and to particle layering within...
A freely suspended drop in a thermal gradient migrates to the hot side since surface tension is usually a decreasing function of temperature. If the drop is attached to a surface with a temperature gradient, the motion is more complicated. The drop either moves to the hot side or cold side, depending on the contact angle and the viscosity ratio. If the surface is patterned, the wettability, or...
Wood is a natural porous bio-polymeric material with complex hierarchical structure. Owing to its exceptional mechanics and sustainability, wood has been an essential material for mankind, in both conventional applications, e.g. building material, and future advanced systems, e.g. green electronics. Sorption of environmental moisture strongly affect wood mechanics, due to the intrinsic...
Groundwater depletion has been significant in the last half century. Different technical developments for expected groundwater replenishment known as managed aquifer recharge have been established to increase the groundwater level. Groundwater salinity is a major problem in many arid and semiarid regions of India where fresh water supplies are limited due to inadequate rainfall and long dry...
Carbonate dissolution processes are significant in environmental and industrial contexts. Development of proper modeling frameworks to tackle, e.g, aquifer contamination, geologic carbon sequestration, disposal of toxic waste or hydraulic fracturing of hydrocarbon reservoirs requires enhanced and detailed knowledge of mineral dissolution/precipitation reactions kinetics. Advanced measurement...
Inkjet printing consists of the ejection and deposition of ink droplets on substrates that are moving underneath the printhead [1]. For printing on paper, water-based inks have been developed that are beneficial from an environmental standpoint. The printing of semi-infinite or long lines on moving paper substrates lead to a steady-state distribution of moisture and heat which are a suitable...
Soft and porous materials are present in a variety of contexts, from pharmaceutical applications to fundamental physics of interfacial soft matter. In particular, an intermediate layer of a soft material, present between a liquid phase and a solid boundary, can induce remarkable changes in lubrication mechanics. The motion of colloidal particles above a nanoscale grafted polymer layer is just...
To this day, the petroleum industry is still searching for alternative ways to improve hydrocarbon recovery from the reservoir. The residual oil blotches may consist of about 30% - 40% or more of a volume fraction. The interest in applying Enhanced Oil Recovery (EOR) techniques on the additional amount of oil is because conventional methods cannot produce it. EOR is one option of the...
Moisture transport characteristics of porous materials play an important role in many industries. For example; packaging materials which can be directly related to shelf life and packaged product stability; model membranes which are widely used in in-vitro permeation studies in skin care industry; and electrospun nanofibres for polymeric scaffolds. Moisture vapour transmission rate (MVTR)...
Coronary heart disease is characterised by the formation of plaque on artery walls, restricting blood flow. If a plaque deposit ruptures, blood clot formation (thrombosis) rapidly occurs with the potential to fatally occlude the vessel within minutes. Von Willebrand Factor (vWF) is a shear-sensitive protein which has a critical role in blood clot formation in arteries [1]. At the high shear...
Foam technology has been widely employed for enhancing oil recovery from mature reservoirs as well as the unconventional oil reserves. Employing CO2 as the foam internal phase could not only explore extra oils from reservoirs but also in the meantime store large amount of CO2 in underground formations, thereby fulfill the resourceful utilization and geological storage of the greenhouse gas....
Diverse processes—e.g., environmental pollution, groundwater remediation, oil recovery, filtration, and drug delivery—involve the transport of colloidal particles in porous media. Using confocal microscopy, we directly visualize this process in situ and thereby identify the fundamental mechanisms by which particles are distributed throughout a medium. At high injection pressures,...
Title: Nanofluid Evaluation for Enhanced Oil Recovery
Nanotechnology has the potential to upgrade the oil and gas industry within different areas such as exploration, drilling, production, and enhanced oil recovery (EOR). For instance, the use of nanoparticles as an EOR method exhibit many advantages since: 1)The size and shape of nanoparticles can be easily modified during fabrication. 2)...
Paper-based microfluidic devices are rapidly becoming popular as a platform for developing point-of-care medical diagnostic tests[1]. Capillary force is the main driving force for the transportation of test liquids in paper-based devices. Therefore, a deep understanding of its internal capillary flow are indispensable for designing sensitive and accurate paper-based point-of-care medical...
Nanotechnologies have recently been proposed for use in conformance control applications to modulate the release of cross-linking agents, facilitating deeper placement of polymer-gel systems. In any potential nanotechnology application for improved conformance, large-scale nanocapsule mobility (100s of meters or more) and precise control of crosslinking agent release rate or time (up to few...
Flows containing suspended colloidal particles and dissolved solutes can occur in a variety of natural and engineered scenarios. With an objective of designing technological applications including effective separation techniques, it is desirable to gain control over the particle dynamics. Diffusiophoresis or the chemotactic migration of colloidal particles due to local chemical gradients was...
Surface characteristics are important at the micro- and nano-scale level. Surface roughness is one of the main factors influencing the contact angle, as it increases the solid-fluid interfacial area and leads to the droplet impingement on sharp edges of a rough surface. In addition to the surface roughness, anisotropic wetting of chemically heterogeneous surfaces can be a driver to control the...
A Kozeny-Carman based model of permeability is extended by incorporating information about the local structure of the void space. Furthermore, it is demonstrated how this added structural information can be retrieved from a three-dimensional digital image of a porous material. The proposed model is validated with both foam- and water-deposited high-porosity laboratory sheets made of CTMP and...
Objectives/Scope: There have been many reports on EOR by low salinity water flooding. An inevitable phenomenon of low salinity water flooding is that clay minerals would undergo hydration expansion and be washed off from the rock, and then migrate in the pore throat. In this study, a 2.5D visualized microfluidic model is used to observe and analyze various phenomena during the migration of...
Countercurrent spontaneous imbibition (SI) is an important flow mechanism to recover oil in water- and mixed-wet porous media by means of capillary pressure. Experimental imbibition tests conducted in conventional core samples and numerical simulations show that oil recovery as a function of time occurs in a characteristic S-shaped form, which describes the infinite acting and the...
Determining the macroscopic properties of heterogeneous materials requires detailed knowledge of their porous structure. The most widely used experimental methods allow obtaining high-quality bi-dimensional images of porous media samples. At the same time, direct investigation of three-dimensional samples is a technologically complicated process and requires expensive laboratory equipment....
Within the past years, Additive Manufacturing (AM) technologies could be established as a versatile complement to conventional means of manufacturing. Especially provided opportunities such as handling complex geometries and gaining control of various process parameters have become a driving force towards its use for industrial applications. Being data-based, AM technologies also allow a high...
The interest on thermal conductance of polymeric ion-exchange membranes is increasingly important due to the growth of new energetic technologies based on transport processes through membranes. The relative importance of the thermal conductance is directly related to the desirability of isolating or enhancing the energy transfer to achieve the optimum performance of diverse membrane-based...
Layering is widely recognized in geologic porous media at multiple length scales ranging from the micrometer scale to the km scale. Incorporating the impact of the multi-phase flow on such heterogeneity on field-scale simulations demands upscaling not only of absolute permeability, but also the saturation functions; relative permeability and capillary pressure. If done correctly, upscaling of...
We present preliminary results from experiments investigating fluid transport in partially wet porous media. Our experiments mimic the natural processes that happen for example when a water-soluble pollutant is spilled on humid soil and is gradually transported inside the network, following the gradient of the matrix potential. We utilize a synthetic quasi 2D matrix of glass beads in a...
Digital rock physics (DRP) is the derivation of rock properties from scanned volumes of core plugs [1]. The scanning modalities include 2D-based techniques such as light sheet microscopy, scanning electron microscopy and confocal microscopy, which gives slice-wise information of the rock, and 3D-based techniques such as clinical x-ray tomography, cone beam computed tomography (CBCT), and...
In the pharmaceutical industry, different methods have been developed to analyze the internal structure of solid dosage forms such as mercury porosimetry, and gas adsorption (1,2). These methods are destructive and unable to study the dynamic property of a sample during dissolution. Hence there is a growing demand for developing non-destructive techniques to visualize and characterize the...
Understanding the physical mechanisms of unsaturated flow in fractured vadose zone at different scales is an important for subsurface hydrology. Here we develop a network model to study infiltration in unsaturated fracture networks. We consider an idealized fracture network composed of a series of Y-shaped intersections. At each intersection, liquid storage/release and splitting/convergence...
Despite recent advances in synthesis and manufacturing of porous materials and devices, producing porous structures with targeted properties is still an expensive, trial-and-error procedure. A powerful way to accelerate this process and to guide manufacturing is to use numerical design of porous media. Current numerical porous media design methodologies typically include a random...
Electrokinetic phenomena occur in porous media as a result of the application of electric potential gradients. This technique has great potential for remediation of soil and groundwater even in challenging low-permeability porous media. The applied, low-intensity electric fields can enhance the transport of contaminants and the delivery of reactants and amendments for in situ (bio)degradation....
X-ray Computed Tomography (CT) methods can be employed to study the internal structure of porous geomaterials non-destructively and with minor sample preparation. Previously, such methods have been utilized in the characterization of petroleum reservoirs, underground water resources, soil, and carbon storage in aquifers. X-ray CT has the potential to characterize porous geomaterials at...
Multiphase flow in porous media has high societal relevance, for example in geological CO2 sequestration and gas diffusion in fuel cells. Intensive research over several decades has been conducted on multi-phase flow in two dimensions using setups such as Hele-Shaw cells[1,2]. Advances in X-ray sources and detectors have made time-resolved studies of flow in three-dimensional porous media...
Volume changes on mixing can significantly affect the flow of non-ideal mixtures in porous materials. In the case of a significant excess volume, the law of conservation of volume, instead of mass, governs flow equations. Such profound thermodynamic effects affect the modeling of many multicomponent fluid flow processes in porous materials. Despite theoretical advancements in this regard,...
Bubbles dispersed into a liquid phase create a wet foam, which is a complex fluid with a volume fraction of the gas phase up to 97 vol.\%. It controls the flow front by the Jamin Effect and directs the fluid into areas that were previously difficult to reach by water or gas. Nanoparticles have been used to stabilize bubbles. They can adsorb at the gas-liquid interface providing enhanced...
Enhanced Geothermal Systems (EGS) is an effective way to develop deep geothermal energy at high temperature, in order to improve the thermal recovery efficiency of EGS, the multi-stage hydraulic fractured horizontal well technology can effectively transform the reservoir, making the fracture generated by hydraulic fracturing the main heat transfer channel and improving the heat transfer...
In this work, we study uncertainties originating from foam flood models' responses concerning non-Newtonian behavior. This work presents how uncertainty affects foam rheology and analysis of Newtonian and non-Newtonian foam formulations. To this end, the Markov Chain Monte Carlo (MCMC) technique was used to estimate parameters for the different foam models. In addition, a global sensitivity...
We will be dealing with various models from porous media stemming from applications in filtration processes. Our models includes the reaction diffusion and the convection diffusion models coupled with a stochastic differential equation.
Our models are highly heterogeneous in time and space.
Our main result consists of deriving the macroscale equation. We show that the resulting macroscale...
This work aims at advancing our understanding of the mobility and entrapment of nanoparticles (NPs) in porous media. The findings of this study are important for remediation of contaminated groundwater using nanoparticles (e.g. zero-valent iron). We focus on identifying the key NP transport mechanisms at pore scale in a non-destructive way using X-ray computed micro-tomography (X-ray...
At present, we are facing two challenges of the increasing demand on energy rescources and the increasing discharge of CO2. In one hand, the newly exploited oil and gas reserves consist of high proportion of low permeability reservoirs, which are difficult to be developed. On the other hand, astonishing amount of CO2 is discharged into the atmosphere accompanying the fossil energy consumption...
In the next 20 years, there will be a large number of offshore oil fields to complete oil and gas exploitation. The removal of offshore platforms in resource exhausted areas is the mainstream treatment method at present. However, it is expensive to use large-scale offshore equipment, and there is little research on the reuse of offshore platforms. Based on the analysis of the current situation...
DNA tracers have been applied in groundwater systems in order to track flow paths and travel times, and to identify hydraulic connections. In this study, we aim to develop a blueprint of the application of DNA tracers to determine hydraulic conductivity, effective porosity, and dispersion. Also, we aim to minimize the uncertainty in estimating the parameters. Two well-controlled laboratory...
Growing world population and global warming impact the quality of water resources on a global scale. Eutrophication, the process of enrichment of water by nutrients, is considered one of the most common causes of water quality impairment. A direct outcome of eutrophication is an increase in the production of algae. In northeastern Brazil, a semi-arid climate region, cyanobacteria dominance and...
Single and multi-phase flow are encountered almost everywhere, including biological and chemical processing, offshore applications, oil and gas recovery, corrosion and naval hydrodynamics. Extending the physical understanding of single and multi-phase flow is of key importance of many industrial applications. High-speed visualization, such as particle image velocimetry (PIV) has been...
Low salinity water-flooding is an EOR method that potentially modifies the equilibrium of the crude oil/brine/rock (COBR) system to a condition that allows additional oil to be mobilized in the porous media. The uncertainties associated with this EOR method, which has been demonstrated extensively in sandstones and some carbonates, are greater when dealing with a realistic crude oil containing...
Pollution of soil-water resources due to industrial, domestic and agricultural activities is a growing concern. The polluted soil-water systems contain a mixture of organics, heavy metals, hydrocarbon oils, emerging compounds etc. These ‘pollutant cocktails’ exhibit interesting interactions by altering chemical activity of individual pollutants in the system. Heavy metals and petroleum...
Three-dimensional high-resolution images, obtained from X-ray micro-computed tomography (μCT) in a non-destructive and non-invasive manner, can be used in digital rock physics (DRP) studies, including property characterization, hydraulic and mechanical behaviour modelling, flow and transport simulation, etc [1, 2]. In recent years, machine learning received great success in various fields of...
Hysteresis in transport properties such as relative permeability remains a challenge for reservoir simulations of multiphase processes such as CO2 sequestration as well as chemical enhanced oil recovery (EOR). Modeling relative permeabilities as a state function with the knowledge of the parameters that affect relative permeabilities has shown promise in mitigating hysteresis.
In this...
Accurate modeling and prediction of flow and reactive transport in fractured and porous media under uncertainty requires characterization of unknown model parameters such as permeability, hydrodynamic dispersion coefficient, and/or reaction kinetics, with their estimation uncertainty. Sensitivity analysis of such parameters plays an important role before or during the uncertainty analysis by...
Recent advances in image data science, data storage and high-performance computing have enabled the application of machine learning and data-driven approaches to a wide range of discipllines. Image data analysis in the geosciences and phase idetificantion from core analysis have allowed significant developments in the characterization of structural, compositional, storage and transport...
Although several investigations on the waxy crude oils have been conducted, there are no adequate research studies on the prediction of the apparent viscosity of waxy crude oils mixed with polymeric inhibitors. In this study, multi-gene genetic programming (MGGP) as a powerful intelligent model is used to develop an accurate and efficient mathematical model to relate process input parameters...
Water flow in nanoscale channel is known to be affected by the strong water-wall interactions which induces that the flow significantly deviates from the conventional continuum flow. Vast experimental observation and simulation results in recent literature shows higher/lower-than-expected flow capacity in nanopores. Currently, most research are limited on the simple geometry with circular...
The filter cake formation during overbalanced drilling, and later on, its displacement and rearrangement during production are key parameters that impact formation damage, fluid loss control, and ultimately, effective production of hydrocarbon fluids. To address these issues, we investigate the impacts of non-Newtonian fluid rheology and pore space topology on the inner filter cake formation...
BZ oilfield in Bohai Bay is a fractured porous metamorphic reservoir, which shows the characteristics of double porosity and double permeability. The mechanism of condensate reverse evaporation is also different from that of general sandstone condensate gas reservoir. In this paper, firstly, the metamorphic core without fracture was obtained for porosity and permeability test (average porosity...
In this work, we investigate the capacity of Generative Adversarial
Networks (GANs) in generating unrepresented patterns in a geological
dataset. The new unrepresented patterns in the training dataset are as-
sumed to belong to the same original data distribution. Speci?cally, we
design a conditional GANs model in a supervised training of GANs, to in-
terpolate geological properties...
Methane is recognized as a potential energy source in the transition to carbon free energies. Appropriate modeling approaches to quantify methane migration in low permeability geomaterials can assist the appraisal of the feasibility of a methane recovery project. Wu et al. (2016) proposed a model enabling one to estimate the total mass flow rate of the gas as the sum of key processes,...
Classical models for two-phase flow in porous media are based on a capillary pressure-saturation relationship. Based on the assumption of thermodynamical equilibrium, this relationship is commonly written as $P^n-P^w=P^c(S^w)$, where $P^w$ and $P^n$ denote the fluid pressures of the wetting and non-wetting fluid phases, and $P^c$ is the capillary pressure which depends only on the saturation...
Abstract— The approach of using machine learning related or deep neural networks for semantic segmentation has highly been successful in various areas of research irrespective of the levels of complexity of the structural patterns involved in images of interest. With the adoption of unsupervised learning, human-related errors in segmentation may be suppressed and process time saved. However,...
Salt water is ubiquitous in nature (e.g. geomaterials, soil, clouds formation) and in technology (e.g. desalination, concrete weathering, heritage conservation). In most of these situations, salt water is confined within a porous medium, often with pores down to the nanometer scale: for example, crystallization and dissolution cycles induced by humidity changes are known to induce structural...
X-ray CT imaging, which provides a 3D view of a sample, is a powerful tool for investigating the internal features of a porous rock. Classifying phases in these images is highly desirable but, like any other digital rock imaging technique, is time-consuming, labor-intensive, and subjective. Combining 3D X-ray CT imaging with machine learning is a promising, powerful method that addresses the...
Petroleum reservoir modeling procedure for production optimization is a complex problem and requires significant computational costs -rooted in reservoir simulation and post-processing. The advent of Artificial Intelligence -particularly supervised machine learning algorithms- in the petroleum industry is gained much popularity because of efficient functionality in terms of high dimensional...
Methane mostly makes up the constituent of shale gas and it is currently being exploited in fulfilling the world’s energy demands [1]. Molecular simulation techniques including Density Functional Theory (DFT) and Molecular Dynamics (MD) techniques are employed to understand methane transport in the pores at typical reservoir conditions [2]. To simulate the shale model which in reality is made...
Over the last decades shale gas production from deep rock formations has become increasingly important in the gas industry. This has led to thorough examinations of fluid transport properties by molecular dynamics simulations in the organic part of the porous medium, such as those found in unconventional reservoirs, so called kerogen. Most of these studies have been done by considering the...
Image analysis of micro-CT (computed tomography) images, which can provide nondestructive evaluation of rock properties (porosity, permeability, etc.), is largely dependent upon optimum segmentation of the image objects. Traditionally, images are segmented using pixel threshold values derived from statistical analysis (e.g., Otsu thresholding method). However, the statistical threshold...
Subsurface fluid flow prediction is critical in many natural and industrial processes such as groundwater movement, oil extraction, and geological carbon dioxide sequestration. These processes are controlled by the permeability of the underground porous media (i.e., soil, rock, etc.). Traditionally, the permeability of porous media is determined via expensive and labor-intensive lab-based...
Majority of porous solids used in industrial processes such as energy storage, separations and catalysis possess structural disorder over varying length scales. These disorder effects strongly affect the properties of the confining fluids in the pores. Hence, detailed quantification of structural disorder with correlation to fluid phase behavior is a necessary step towards optimization for...
Production from gas condensate reservoirs can be significantly improved with gas injection. Several approaches to the method have been proposed in the literature, aiming pressure maintenance in the reservoir and/or re-evaporation of the deposited condensate, with promising results. However, the effects of complex phase behavior arisen from the interaction between injected gas and accumulated...
Matrix permeability is one of the most important characteristics of reservoir rocks yet its accurate measurement is often challenging for ultralow permeable shale and tight formations. Permeability of these reservoirs is in the range of micro-Darcy to nano-Darcy and depends on several factors including confining stress, pore pressure, pore fluid, and temperature. Hence, determination of...
We present surface-washing experiments modelling the decontamination of porous substrates.
Firstly, we report a protocol to manufacture well-defined porous media by sintering glass ballotini (< 1 mm) to form free-standing homogeneous porous plates or incorporating a non-porous solid glass backing and/or surrounding: the resultant samples are mechanically stable cuboids. The ability to...
Understanding fluid phase behavior is of primary importance in different industries, including oil and gas exploration and production. It is known that nanoporous confinement plays a vital role in determining the phase behavior of fluids hosted in the rock pore space. While some quantitative understanding is available describing pure fluids' behavior in nanopores, surface chemistry's effects...
A two-scale poromechanical model incorporating the complex adsorption phenomena of a fluid mixture in nanopores is developed in this work. The porous medium is composed of a solid phase and nanopores of size of several nanometers where adsorption occurs. The adsorption isotherm of a fluid mixture is rigorously constructed by using the Density Functional Theory (DFT) and the Fundamental Measure...
In recovery of hydrocarbons from the subsurface wettability plays a key role. Wettability is a property controlled by the crude oil-brine-rock (COBR) interactions. It is known that wetting properties of a rock contributes to the microscopic oil displacement efficiency and the ultimate achievable recovery factor. Rocks (or rather minerals composing them) are water-wet at their initial (clean)...
Permeability and porosity are two most important parameters of rocks for evaluation and exploitation of oil/gas reservoirs. In this study, a modified pulse-decay method has been developed to measure both permeability and porosity simultaneously. In the proposed method, the gas pressure in one chamber is changed (increased or decreased) instantaneously and then maintains constant, while the...
Improving the durability and lifespan of concrete transportation infrastructure is a major concern. Penetration of aggressive agents such as chloride ions is known to accelerate structural decay. Several nanotechnology-based treatments intended to decrease permeability are currently under study. The use of nanosilica as a surface treatment has proved to be one possible solution, particularly...
Capillary imbibition, i.e. the spontaneous flow of a liquid into fine pores and cracks without the assistance of external forces such as gravity, is universal and critically important in many natural processes and industrial applications. On the nanoscale, the intensity of solid–liquid interactions (εS–L), which controls the wettability of the capillary walls, plays a critical role and...
Microbial growth and biofilm formation are to be expected in many water circulation systems as it is also the case in production facilities for packaging materials. Consequently, these factors can impair the production, may lead to increased downtime and higher costs. Therefore, this study focuses on the determination of microbial composition of different phases involved in the manufacturing...
Under the contradiction of the fast depletion of oil production from conventional reservoirs and the increasing energy demand, unconventional oil and gas reservoirs, such as tight oil, tight gas and shale gas, have played more and more important role in the world’s energy supply. Gas injection process has contribute one of the most efficient oil recovery methods on tight oil recovery...
The effectiveness and reducibility of the methane combustion kinetic mechanisms were examined for the TPOX process in a porous medium. To this end, TPOX was successfully simulated using ANSYS CHEMKIN-Pro through a reactor network model composed of perfectly stirred and honeycomb-monolith reactors. The efficacy of six chemical kinetic mechanisms was compared for the equivalence ratios (ERs)...
Biofilm growth in porous media changes the hydrodynamic properties of the medium: porosity and permeability are reduced, and dispersivity increases. However, the first arrival of breakthrough curves (BTCs) is more reduced than derived from the reduction in porosity, and the BTC tail becomes heavier. These observations suggest the need of multicontinuum models (Multirate-Mass-Transfer, MRMT)...
We numerically study the effect of differential diffusion in chemically-driven convective dissolution that can occur upon the reaction of a dissolving species A in a host phase when the chemical reaction destabilises an otherwise stable density stratification. For example, an A+B→C reaction is known to trigger such convection when, upon dissolution into the host solution, A reacts with B...
Accuracy of rock image segmentation is the base of digital rock, and decides the credibility of subsequent physical calculation. However, it spends much time to acquire perfect segmentation result. Benefitting from the advances in hardware and algorithms, deep learning has been widely used in image process for it doesn’t need the complex image preprocessing comparing with conventional...
Towards the quest for accuracy and efficient characterization of heterogeneous cretaceous carbonate, the path for geology and data scientists is full of challenges. The main challenge for achieving both accuracy and efficiency simultaneously is the ability to have the machine understand the heterogeneity effect on the rock's physical properties. From rock micro-Computed Tomography (uCT) images...
The technology of CCUS(carbon capture,utilization and storage) has great potential for development. It is of great significance for CS-ESGR (CO2 sequestration and enhanced shale gas recovery) to study the dynamic adsorption characteristic of CO2 in the organic pore of shale. Most studies analyze the adsorption efficiency and influencing factors at the level of results, while less attention is...
The high heterogeneity of shale is a deterrent in the accurate assessment of reservoir characteristics, making gas exploitation a challenging task. Besides being a nearly impermeable permeable reservoir type, shale has a complex pore network exhibited by various pore types and pore-size distributions that influence gas storage and transport in the shale matrix [1,2]. Gas in shale is stored as...
Our study aims at investigating the interplay between the dissolution, precipitation and transport processes taking place within randomly heterogeneous conductivity domains and the ensuing spatial distribution of preferential pathways. We do so by relying on a collection of computational analyses of reactive transport performed across two-dimensional systems where the (natural) logarithm of...
Shale gas reservoirs which are usually heterogeneous ones have a multiplicity mode of occurrence. A comprehensive understanding of the complex migration mechanism is prerequisite to fully comprehend the reservoir seepage. In this paper, the gas flow types are classified based on Knudsen number; the aperture distribution is introduced as the weight coefficient of the comprehensive constitutive...
With the development of massive gas injection in shale and tight reservoirs, the multiphase behavior of nanoscale pores before and after gas injection has attracted increasing attention. A large number of published literature have shown that due to wall adsorption and capillary forces, the phase behavior of fluids in micro and nano pores is significantly different from that of conventional...
Microbially induced calcite precipitation (MICP) in soils can be fundamentally explained by combined theories of reactive transport and metabolic-related biological activities in porous media. Still, it is challenging to describe both the biofilm growth and mineral precipitation at smaller scales, yet their competition and effects on larger-scale transport behaviors remain unclear. To advance...
Porous media is the key energy conversion media in two-step solar thermochemical fuel production devices. The conventional way of fabricating porous metal oxide structure shows limited flexibility in varying local morphology for better transport properties. The material structure optimization is hindered by lack of methodology precisely tuning material structure and lagged modeling framework...
The pore structure of shale oil reservoir is complex, and the shale cores are hard to acquire. Accurately characterizing the pore structure of shale reservoir is the key to study the fluid seepage law in shale reservoir. Based on the three-dimensional focused ion beam scanning (3D-FIB-SEM) images of real shale cores, the structure of the original generative adversarial network model is...
Quantitative evaluation of rock fracture properties including aperture, roughness and orientation is very important for rock mass characterization as the fractures properties control hydraulic and mechanical behavior of the rock. In an X-Ray CT slice, fractures are appeared as arbitrary-oriented curve-like object with low gray-scale intensity. Fracture geometry information can be obtained...
Bacterial autoaggregation is a phenomena widely exhibited by environmental and pathogenic bacterial species [1]. Autoaggregation is mediated through surface bound and secreted proteins and polysaccharides and can act as a precursor to surface bound biofilm formation. Aggregation is considered a survival strategy, commonly induced by unfavourable growth conditions and low metabolic activity...
This study assumes complex saturated liquid phase volume to be a triple porosity medium consisting of macro, meso and micropore structure. This provides the Triple Porosity Non-Equilibrium (TPNE) model a higher capability of mimicking the physical and chemical non equilibrium present as per the field conditions. The method of finite difference for discretisation is used to solve the model....
Wind erosion (dust) is a severe problem for mine tailings industry, as it poses environmental and safety concerns to public. Biological induced precipitation methods are found to be able to improve the resistance of soil for wind erosion. In this study microbiologically carbonate precipitation (MICP) based on urea hydrolysis was used to stabilize the surface of different tailings materials. An...
The production rate for horizontal wells of shale oil is low. In order to achieve the economic and effective development, hydraulic fracturing technology is often adopted. After hydraulic fracturing, wells have a high production rate in the initial stage. After a period of production, the production rate will drop rapidly, and then will maintain at a lower level for a long period of time. The...
Enzymatically Induced Calcite Precipitation (EICP) in porous media can be used as an engineering option to achieve targeted precipitation in the pore space. It is associated with an alteration of porosity and, consequently, permeability. A major source of uncertainty in modelling EICP is in the quantitative description of permeability alteration due to precipitation, based on commonly applied...
We will present our recent results on porosity (P), permeability (K), and tortuosity (T) of artificial, randomly generated porous medium predicted directly from the geometry images [1]. We will show that convolutional neural networks (CNN) can predict porosity, permeability, and tortuosity based only on the obstacles' picture. The CNN is trained on artificial data samples, for which the...
Subsurface storage of CO2 involves the injection of CO2 into suitable geological formations and the monitoring of the injected plume over time. The science and technology of CO2 geo-sequestration has been maturing over the last two decades. To increase the effectiveness of the underground CO2 sequestration, the multi-phase-flow and its relevant mechanisms that change the distribution and...
Liquid-infused nanopores play a pivotal role in many natural and technological processes ranging from transport across biomembranes and plant movements to templating processes for nanomaterials and modern concepts of water desalination. Here I will present three experimental studies aimed at the fundamental exploration of wetting and imbibition dynamics in and at nanoporous surfaces (1) as...
