As an unconventional gas resource, coalbed methane (CBM) reservoir has unique flow mechanism and production scheme compared with conventional and other unconventional gas reservoirs. The permeability of coal cleats system varies with the production of water and gas, in order to accurately forecast gas productivity, the dynamic permeability model should be investigated first before establishing...
We consider a porous medium where the pore space is completely filled by three different phases: two immiscible fluids like water and air or oil and a solid phase. The non-wetting phase contains no solute and has no interaction with the solid phase. The wetting phase contains dissolved ions, which can precipitate at the pore boundary to form the solid phase. The reverse process of dissolution,...
Atomic level simulations, such as molecular dynamics (MD), Monte Carlo (MC) or DFT, have recently become indispensable tools for characterization of porous materials [1]. Computational methods are often used to study adsorption, diffusion or separation mechanisms. Here, we perform density functional theory (DFT) calculations of structural properties of flexible and rigid nanoporous MOFs. For...
To establish and maintain well integrity to avoid leakage through wells is vital for production wells relevant for the petroleum industry, and for injection wells used for CO2 sequestration. To ensure that stored CO2 remains underground in a long-term perspective it is of the utmost importance to optimize the integrity of both active and abandoned wells. The properties of well barriers such as...
Extracting connected micro-fractures from 3D XRT images of carbonate and shale core samples is critically important to perform numerical fluid transport simulation in porous media, but difficult to honour their true connectivity because they are often distorted by noises, artefacts and the complex intersections among the fractures to appear disconnected in the imagery. These challenges can be...
This study describes wettability alteration mechanism of calcite surface by low salinity water (diluted seawater) and ion tuned water (regarding to potential determining ions, PDI). The contact angles of brine droplets on calcite surfaces that immersed in oil were measured. The relative ability in modifying the surface wettability of these three ion species (Ca2+, Mg2+ and SO42- ions) thus is...
Abstract
Transport of charged species in porous media is significantly affected by the electrochemical migration term resulting from charge-induced interactions among dissolved ions. Such electrostatic interactions during multicomponent ionic transport have been investigated both in diffusion-dominated systems [1-3] and, recently, in advection-dominated systems for steady-state plumes...
The microstructure of a radioactive waste confinement barrier strongly determines its flow and transport properties. Numerical flow and transport simulations for these porous media at the pore-scale are necessary for in-depth understanding of the pore-scale processes, and might for instance allow making predictions beyond current experimental timescales. Such simulations of course require...
The world cultural heritage Yungang Grottoes, created in the sandstone is seriously degraded due to the intrusion of salty ground water, resulting in the blurred image and unclear facial features, which need urgent restoration and rescue. In this paper, we study how to use Microbial Induced Carbonate Precipitation（MICP）by the percolation method to stabilize the sandstone samples taken from...
Abstract
Immiscible two-phase flow in porous media is a process encountered in various applications such as oil recovery, soil remediation, CO2 sequestration and some other industrial systems. Almost all models of two-phase flow are based on Darcy law, which is valid only for the phases that form a continuous domain. But, there exist many applications where one of the fluid phases is...
In their seminal works, Taylor and Bretherton showed that when a wetting viscous liquid is displaced by a less viscous non-wetting fluid in a capillary tube, a film of the defending liquid is left on the walls. Here, we revisit this classic problem in the partial wetting regime using both experiments and theory, and show that the flow dynamics drastically changes from the classic picture. We...
The frozen food products are subjected to freeze-thaw cycles during storage and shipping. These cycles result in ice recrystallization, surface dehydration, and solute and moisture diffusion, which damage the foods quality. The re-crystallization phenomena involves multiscale characteristics spanning from the scale of polymers to macroscale. The transport of moisture and vapors is complicated...
The competition between different driving forces (pressure gradients, gravity, internal friction, etc.) typically leads to various instabilities together with the development of a wide range of visually impacting patterns. The particular case of frictional flows, which consists in the displacement and structuring of a granular phase under viscous or capillary stress, can be considered as a...
Bayesian seismic inversion can be used to sample from the posterior distribution of the velocity field, thus allowing for uncertainty quantification. However, traditional Markov chain Monte Carlo (McMC) can be extremely computationally expensive. In this presentation we compare recently proposed, computationally effective McMC methods, such as a two-stage [1,2], a Hamiltonian procedure [3],...
Subsurface systems are well known to have variations in wettability. Evolving models to describe such systems must be evaluated and validated, and highly resolved experimental observations can play a central role in this endeavor. Quantities such as interfacial areas and curvatures are examples of quantities that are not often measured in high resolution as a function of wettability. ...
In this work a methodology is presented for modeling a fractured porous media and to simulate oil recovery by low salinity water injection through a fractured core. To represent the porous matrix a continuum approach is employed whereas for the fractures a discrete one. Thus, the fractured core is modeled with mixed dimensions elements, representing the fractures as elements of n−1 dimensions...
Research in geotechnical applications of artificial ground freezing is important task in maintaining the stability of engineering structures in permafrost. Safe design require a correct prediction of the coupled thermo-mechanical behavior of soils. Mathematical model of process of thermal stabilization (artificial freezing) on the classical Stefan model is built.
A feature of the modeling of...
Elastic moduli are amongst the most important parameters to assess the shale plays and to instruct the hydraulic fracturing. However, due to extremely high brittleness of shale and very limited samples available, the conventional methods to obtain elastic properties, for instance, uni-axial or tri-axial compression tests, often encounter with early breaking apart of shale samples, which leaves...
An experimental observation of the structuring of a granular suspension under the progress of a gas/liquid meniscus in a narrow tube is reported here. The granular material is moved and compactifies as a growing accumulation front. The frictional interaction with the confining walls increases until the pore capillary entry pressure is reached. The gas then penetrates the clogged granular...
Due to the existence of electric double layer in fluid-saturated porous media, Acoustoelectric effect will occurred when acoustic waves propagate through media. In the logging while drilling environment the drilling collar might be taken as a shear source. SH-TE acoustoelectric logging is a potential method to obtaining shear wave velocity directed in LWD environments. When the interface exist...
A water infiltration rate into soil or porous media is reported to be slower in microgravity than on the earth with 1G (Jones and Or, 1999) as well as for hydrophobic soils (DeBano, 1971). Water characteristic curves under the microgravity condition (Heinse et al., 2007) and for hydrophobic soils (Bauters et al., 2000) very much look alike little changes in matric potential with various water...
Heat conduction in porous materials is of great interest for geological and engineering studies including geothermal reservoirs, insulating layers, composite materials, to name a few. In the absence of flow, thermal energy is transferred through the constituting materials of porous media with different capabilities in conducting heat. Thus, the structure of phase boundaries, the contact area...
Many technical materials, biological tissues and living cells are ionized porous media. Under changes of osmotic boundary conditions, these ionized gels respond by swelling to many times their own volume. As the macromolecular network of the gels has limited strength, fracture propagation may occur. Modelling of 3D finite swelling and subsequent fracture requires very careful modelling....
Several biological processes have been developed in the recent years in which the hydro-mechanical soil properties can be modified by precipitating calcium carbonate. Microbial and enzyme induced carbonate precipitation (MICP and EICP) have gained interest in potential biological processes to improve the mechanical properties of the soil by precipitating calcium carbonate, which forms...
In this study, slip flow of gases were measured in several tight reservoir rock samples and nanofluidic chips. The results were then compared to gas flow simulations by DSBGK. Klinkenberg permeability of rocks was obtained using a steady-state method under varying pore pressures but constant temperature and effective stress. Experiments conducted in nanofluidics devices, which have controlled...
A technique for studying flow in porous media at the lab scale has been previously developed in our laboratory. The technique involves a confined miniature cylindrical geometry that is obtained by heating and pulling on a 100ml cylindrical capillary. The narrow region of the capillary, tapered and cylindrical, is filled with cryolite to form a random, porous medium, and two-liquid-phase-flow...
Controlling fluid flow through permeable and fractured media is important in a variety of subsurface contexts including geologic carbon storage (GCS). Low pH and or high salinity conditions create corrosive aqueous environments which would rapidly degrade cement in wellbores or carbonate/clay features in caprocks. Our group has explored the potential to deploy dissolution/precipitation...
Abstract: Eight gas-water relative permeability curves of natural ultra-low permeability cores were tested from a new steady experiment at eight different permeability levels. The absolute permeability is the gas permeability at irreducible water saturation. The results show that the curve have displayed a very sharp decrease in gas relative permeability while a slow increase in water relative...
Treatment of water for human consumption often involves filtration through reactive porous media, such as activated carbon, or metal oxides. The sorption of contaminants inevitably leads to a depletion of available free sites and therefore a decrease in efficiency. A possible technique to regenerate filtration systems is the use of chelation agents. Such compounds, i.e. ...
The progress of the interface between an invasive fluid and a defending mixture of granular material together with a second fluid, immiscible with the invading phase, has recently been used to form complex patterns in both Hele-Shaw cells or millifluidic confinements. These are the result of the deformation of a confined porous material, made of an homogeneous granular phase, into an...
Capillary flow penetration can be categorized into two directions: Unidirectional (Linear) and Radial. The fluid invasion physics has been extensively studied for linear flow direction. Danino & Marmur study radial capillary penetration in a filter paper experimentally, and the results indicate a power-law correlation between average wicking radius and time. It shows the average spreading...
State of the art multi-dimensional nuclear magnetic resonance (NMR) relaxometry and diffusometry techniques along with magnetic resonance imaging (MRI) are applied to explore and characterize phase change in complex systems. High-field NMR techniques are highly sensitive to the thermodynamic phase of the system as well as restrictions on molecular motion. High resolution imaging along with...
Digital Rock Physics (DRP) has made many useful results in the petrophysics (Saenger et al., 2011). Because of the contradiction between resolution and rock size, DRP can't effectively study the law and mechanism of the impact of macroscopic factors on petrophysical properties of complex reservoir such as sonic, resistivity characteristics. Meanwhile, reservoir rocks are usually highly...
With the increasing demand for enhancing production of oil and gas all over the world, improving oil recovery technologies aiming at developing low permeable and tight oil reservoirs are becoming the focus of current research. To help understanding the mechanism of multiphase displacement in underground reservoir, the microcosmic characterization of porous media must be explored. In recent...
Separate Sensible and Latent Cooling (SSLC) systems have considerably improved performance compared to single vapor compression based system for moisture management in buildings. Such systems often deploy solid desiccant based dehumidifier to absorb the excess moisture from air streams. The steady state and transient characteristic of desiccant materials (micro, meso or nano porous structures)...
Because of the low permeability of shale, fractures typically act as the primary flow conduits in these formations. It is therefore imperative to understand the fundamental processes that influence fracture properties in shale to accurately predict unconventional resource production as well as ensure sequestered CO2 does not migrate out of a storage reservoir. In this study, a novel shearing...
The clearance of the metabolic waste in the body is handled by the lymphatic system. Except in the brain, which appears to be the only organ devoid of lymphatic channels. Indeed, the mechanisms underlying the clearance processes of the brain are still unknown, and the topic sparks debate and controversy. What is clear however, is that dysfunction of cerebral metabolic waste clearance is...
In this work, we have performed an efficient implementation of
the multiscale mixed method MuMM introduced in [1], that is based on a
non-overlapping iterative domain decomposition procedure with novel Robin
interface conditions (see also [2] where the variational formulation of [1]
was presented). We also performed a numerical study to built multiscale
mixed basis functions to find an...
The shale of the lower Silurian Longmaxi widely develops in Changning area of Sichuan basin. In order to study the micro pore structure and pore size distribution characteristics of shale reservoirs in this area. The pore structure of lower Longmaxi shale gas formation is researched by field emission scanning electron microscope (FE-SEM), high pressure Hg injection, low temperature nitrogen...
Relaxometric imaging has already been known in MRI of natural porous media and plants for some decades. Mostly T2 maps are determined due to the relatively short measurement time. However, T2 is often accelerated by diffusion processes in internal gradients caused by the high magnetic field strengths typically encountered in MRI. Therefore, the information can not be unambiguously assigned to...
The purpose of this work is to build a coupled geomechanics-flow model to accurately simulate the in-situ stress and fluid flow in fractured reservoir. The model is developed by iteratively coupling a geomechanics model that uses the Continuum Damage Mechanics as its basis to investigate relationships between fracture dynamic change and pore pressure vary. The coupled model also reveals some...
Application of flow and transport simulators for prediction of the release, entrapment, and persistence of dense non-aqueous phase liquids (DNAPLs) and associated contaminant plumes is a computationally intensive process that requires specification of a large number of material properties and hydrologic/chemical parameters. Given its computational burden, this direct simulation approach is...
The physical processes governing flow and transport in porous media span a wide array of spatial scales. Furthermore, in many applications it would be computationally intractable to resolve each scale of interest. To still capture the effects of the smaller-scale processes, one option is to couple together models of different dimensionality. In e.g. vascularized tissue and root networks, the...
The two-phase flow study is meaningful for mass transfer in various industrial processes, for example the prediction of proppant distribution is of significance due to the fact that proppant placement contributes to the enhanced production of fluids by affecting the conductivity of the fractured reservoir. Since it is difficult and expensive for experiments to consider various conditions and...
In geological carbon storage, understanding main mechanisms affecting migration and redistribution of injected CO2 in aquifers is needed for developing predictive models to assess post injection environmental risks and designing long term monitoring schemes. This work presents experimental and modeling studies to investigate processes contributing to post-injection CO2 plume distribution and...
Fractured carbonate gas reservoir with strong heterogeneity, difficult development， the edge and bottom water invasion increases the complexity of gas reservoir development. Therefore, in order to recognize water invasion rules of fractured carbonate gas reservoir with edge and bottom water and provide the theoretical basis for this type of gas reservoir development, according to the gas...
A three-dimensional (3D) high resolution inner structure of rock sample is premise for pore-scale flow simulation of reservoir. µ-CT is considered to be the most direct way to obtain the 3D inner structure of porous media without deconstruction. However, its micrometer resolution limits its application in characterization of small structures such as nano-pores and channels which are critical...
In view of the present situation of low productivity and the difficulty of water injection development in the tight reservoir. In order to improve the development effect of tight reservoir, select cores with different permeability grade parallel samples, and carried out injection of simulated formation water, active water, CO2 and N2 physical simulation experiment. Combined with nuclear...
The Richards equation is a commonly used model for unsaturated flow through porous media. Using the Darcy law in the mass balance equation, and bringing the resulting equation to a dimensionless form one obtains:
\begin{equation}
\phi\partial_t S=\nabla\cdot\left(\frac{K}{\mu} k_r(S)\nabla (p -\rho g z)\right)+f(S,\vec{x}).
\end{equation}
Here $\phi$ is the porosity of the medium; $z$ is the...
At present, many methods of porous media modeling have been proposed. Among them, the multiple-point statistics (MPS) method has a unique advantage in reconstructing 3D digital rock in that it can characterize long-range connectivity of pore space. The Single Normal Equation Simulation (SNESIM) is one of most commonly used algorithms of MPS. In the SNESIM algorithm, the selection of training...
In order to improve the field productivity, the industries can create new fractured wells to reduce the interval between the initial fractures. However, the production from the initial fractured wells can induce stress reorientation in the vicinity of the fractures. As such, a refracturing treatment in the stress reorientation region can lead to a reoriented refracture which has a more or less...
As one of the most important energy resources, improving the recovery of tight gas reservoir will be great significance. However, the complicated pore structure and special fluid flow mechanism makes it difficult to study with usual experiment methods. To address this problem, a systematic experiment procedure is proposed and applied to Sulige tight gas field. First, the pore structure is...
Clay minerals like kaolin and smectite are among the world’s most valuable industrial minerals. They play considerable role in geotechnical, agricultural, and pharmaceutical applications. The static and dynamic properties of a confined fluid between structured clay surfaces are different from their bulk properties. The difference is related to complex nature of interatomic forces between...
The shale gas flowing in the Nano-scale pore structure in shale formation has the properties of over scale and over flow region. It is difficult to describe the flow pattern by using the conventional flow theory. In this study, a physical modeling test of depletion development and the flowing model of gas flow in the micro-nano pores of shale matrix were studied. Through the pore size testing,...
In the process of thermal recovery and the underground storage of nuclear waste, the porosity and permeability of rock will change significantly from thermal stress. In this paper, a sandstone sample was subjected to heating, porosity examination, permeability measurements and CT scanning. Based on digital core technology, permeability and thermal conduction simulations were performed. The...
Results of high-resolution particle velocimetry (PIV) measurements are presented to explore how the turbulent flow overlying a permeable wall is linked to the underlying pore flow and how their interplay is controlled by the topography of the wall interface and by the wall thickness. Two permeable walls were constructed from uniform spherical elements (25.4-mm diameter) in a cubically packed...
Adsorption is one of the most important ways of coalbed methane stored in the coal seam. Methane diffusion in coal plays an important role in coalbed methane production. Understanding the characteristics of adsorption and diffusion of coalbed methane is keys to correctly evaluate the gas content and effectively enhance the gas production. As well known, most coal seams contain a certain amount...
Calcareous sand is oftenused as the filling materialin marine geotechnical engineering, and it is to be reinforced in practice. The technology of Microbial Induced Carbonate Precipitation（MICP）provides a new cementway to reinforce the calcareous sand.In this paper, we study how to use MICP by the mixing method to reinforce the calcareous sand.The mixing method is very different from the...
Soil liquefaction is a significant natural hazard associated with earthquakes. Some of its devastating effects include tilting and sinking of buildings and bridges, and destruction of pipelines. Conventional geotechnical engineering assumes liquefaction occurs via elevated pore pressure. This assumption guides construction for seismically hazardous locations, yet evidence suggests that...
The interest in developing microbial induced carbonate precipitation as a cement alternative in oil and gas wells stems from the fact that this biotechnology can penetrate pore networks that conventional cement grouts cannot due to their high viscosity. Currently MICP is under investigation as a potential wellbore barrier technology to mitigate hydrocarbon leakage through a) micro-channels in...
The cleat or natural fracture system is a dominant factor controlling the permeability of coal seams. Gas permeability and porosity of coal samples with artificially generated fractures are measured under varying effective stress. Based on the experimental results and the Walsh model, fracture width and roughness are estimated. Considering the fracture aperture and roughness, we present a 3D...
The transport of electrolytes in porous media is affected by physical, chemical and electrochemical processes. Coulombic interactions significantly influence the behavior of electrolyte plumes at different scales, not only in diffusion-dominated conditions but also in advection-dominated flow regimes [1-3]. To model the spatial behavior of charge-induced interactions in multi-dimensional...
Due to the size effect of nanochannels and the strong influence of nanochannel surfaces, these ultra-confined water and oil molecules behave extraordinary differently from their bulk counterpart. Therefore, it is of great necessary to study the adsorption and transport of water and oil molecules in the nanochannel.
In this paper, we investigate the adsorption and transport mechanism of...
Shale reservoirs generally have very low porosity and permeability and complex occurrence and transport state, which lead to its unique L-curve production characteristics, representing complicated flow mechanism. A physical experiment using full diameter core was designed to simulate the full lifecycle development process of the shale gas well. From the experiment, many important and...
Due to intense complexity and heterogeneity of pore and throat structure in tight formation, it’s very difficult for representation. In addition, as there abounds in large numbers of micro-nano pores and throats, boundary layer and media deformation effect on pore scale flow cannot be ignored. Therfore, an accurately representative pore network flow model which couples boundary layer and media...
A three-dimensional lattice Boltzmann model (LBM) is used to predict fracture permeability. The LBM is first verified by comparing the predicted permeability of a straight pipe with a rectangular cross section with the analytical solution. Excellent agreement is achieved for various aspect ratios of the cross section. Then the LBM is used to simulate single phase fluid flow in fractures whose...
Porous media has gained an extensive interest in various thermal management applications. The versatile use of such materials in applications requires a better understanding of the thermal-hydraulic performance. the current study is focused on the evaluation of pressure drop through regular (wire mesh system) and irregular (metallic and carbon foams) porous media. Experiments have been...
Fractured geological formations are ubiquitous throughout the world, and their stress-sensitive behaviors are of primary interest in a number of contexts. In this study, a stress sensitivity experiment on carbonate core plugs in which micron Computed Tomography (μ-CT) technology is applied to visualize and quantitatively evaluate morphological changes to the fracture aperture with respect to...
Sorption competition onto Fe-(oxyhydr-)oxides surfaces is a well-known mechanism controlling the release and mobility of arsenic (As) in subsurface (Dixit & Hering, 2006). Over the last decades, surface complexation models (SCMs) have been implemented to model interactions between sorbants and mineral-oxides surfaces by considering the thermodynamic properties underlying complexation and...
Abstract: To research the influence of interfacial tension of fracturing fluid on spontaneous imbibiton in low-permeability water-wet reservoir, a spontaneous imbibition model was constructed upon a modified LW imbibition model includes hydrostatic pressure and flow resistance with fractal theory, and the relationship between spontaneous imbibition volume and imbibition time was described by...
The geologic sequestration of CO2 is a potential solution for decreasing anthropogenic atmospheric CO2 emissions by trapping it underground. A primary mechanism for storage is structural trapping where low permeability and high capillary entry pressure caprock materials hold back the buoyant CO2 from rising to the surface. The wettability (or contact angle) of reservoir and caprock materials...
Highlights
1. Intracrystalline diffusivities of olefins were estimated by SV (Solid Vibrational) model.
2. Effective vibrational frequencies are calculated by curvature of potential well.
3. Selectivity of propylene in both catalysts increases with temperature.
4. Ethylene to propylene diffusivity ratio obtained in ZSM-5 is 2.3 while in SAPO-34 is 35.6.
Abstract
Light olefins...
We study a simple model for the transport of polymer particles injected along with water in a porous rock containing oil. The main goal of this technique is to recover oil that remains trapped after waterflood. Such enhancement occurs through a microscopic diversion of the water flow caused by clogging of narrow pore throats by the injected particles. The diverted flow may lead to the...
Porous interfaces are encountered across a broad range of length scales, both in natural and engineering flow systems. Understanding the coupling between the free flow and the pore flow is key to accurately predicting many important biogeochemical processes occurring in such systems. This is particularly true when the free flow is turbulent and the coupling involves an intermediate region...
Subsurface fluid injection is a proposed method for the storage of hydrocarbon fuels and the mitigation of fossil fuel emissions. Concerns about leakage exist when storing fluids in the subsurface given their potential to damage functional groundwater aquifers or be emitted to the atmosphere. Defects detrimental to the integrity of subsurface storage systems can occur in and around the...
