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1.
2.
Effects manifested in two-phase flows through anisotropic porous reservoirs with monoclinic and triclinic characteristics
are analyzed. It is shown that in two-phase flows through media with monoclinic and triclinic symmetries of flow characteristics
the position of the principal axes of the phase permeability tensors depends on the saturation and does not coincide with
the position of the principal axes of the absolute permeability tensor in single-phase flows and that going over from single-to
two-phase flow may lead to a change in the symmetry group of the flow characteristics. A general representation of the phase
permeability tensor components is presented and formulas are given for the diagonal and nondiagonal components of the relative
phase permeabilities, which are universal and can be used for anisotropic media with any type of anisotropy (symmetry) of
flow characteristics. A complex of laboratory tests for finding the nondiagonal components of the phase and relative phase
permeability tensors is discussed. 相似文献
3.
This article reports an experimental study of the permeability of fibrous porous media based on air flow. Two glass wools
have been analyzed in three different flow directions to evaluate their anisotropic structure. The usual flow theories such
as Darcy’s law, valid for granular materials, have been shown to apply also to these fibrous media which is a more complex
structure (fiber arrangement, high porous media,…). The intrinsic permeabilities and the anisotropic factors have been determined
from an air permeability measurement based on a standard test for industrial fabrics. The experimental results have been compared
to different models, showing the limits of some simplistic models when applied to our highly porous structures. One model,
Kyan’s model based on the flow around submerged objects, was, however, found to agree with our experimental data. This study
also demonstrates the interesting use of an experimental technique, which is air permeability measurement (water permeability
is not adapted), in the investigation of flow phenomena in a fibrous medium. 相似文献
4.
Lattice Boltzmann direct numerical simulations of turbulent heat transfer over and inside anisotropic porous media are performed. This study considers turbulent plane channel flows whose bottom walls are made from the porous media at the bulk Reynolds number of 2900 with isothermal and conjugate heat transfer wall conditions. Four different porous walls are considered. They are walls with only the wall-normal permeability, with the wall-normal and spanwise permeabilities, with the wall-normal and streamwise permeabilities, and with the isotropic wall-normal, spanwise and streamwise permeabilities. The porosity of the porous walls ranges from 0.6 to 0.8. Discussions on the effects of the anisotropic permeability on turbulent thermal fields are carried out by the instantaneous flow visualizations and the statistical quantities. In particular, temperature fluctuations, turbulent and dispersion heat fluxes are examined both inside and outside the porous walls. Finally, the heat transfer performance is discussed considering the effects of the anisotropic permeability. 相似文献
5.
This article describes a semi-analytical model for two-phase immiscible flow in porous media. The model incorporates the effect
of capillary pressure gradient on fluid displacement. It also includes a correction to the capillarity-free Buckley–Leverett
saturation profile for the stabilized-zone around the displacement front and the end-effects near the core outlet. The model
is valid for both drainage and imbibition oil–water displacements in porous media with different wettability conditions. A
stepwise procedure is presented to derive relative permeabilities from coreflood displacements using the proposed semi-analytical
model. The procedure can be utilized for both before and after breakthrough data and hence is capable to generate a continuous
relative permeability curve unlike other analytical/semi-analytical approaches. The model predictions are compared with numerical
simulations and laboratory experiments. The comparison shows that the model predictions for drainage process agree well with
the numerical simulations for different capillary numbers, whereas there is mismatch between the relative permeability derived
using the Johnson–Bossler–Naumann (JBN) method and the simulations. The coreflood experiments carried out on a Berea sandstone
core suggest that the proposed model works better than the JBN method for a drainage process in strongly wet rocks. Both methods
give similar results for imbibition processes. 相似文献
6.
M. N. Dmitriev 《Fluid Dynamics》2011,46(2):291-298
The Rapoport-Leas mathematical model of two-phase flow is generalized to include the case of anisotropic porous media. The
formula for the capillary pressure, which specifies the relationship between the phase pressures, contains a scalar function
of a vector argument. In order to determine the scalar function, the capillary pressure tensor and the tensor inverse to the
tensor of characteristic linear dimensions are introduced. The capillary pressure is determined by the contraction of the
second-rank tensors with a unit vector collinear to the phase pressure gradients, also assumed to be collinear. It is shown
that the saturation function introduced for isotropic porous media (Leverett function) can be generalized to include anisotropic
media and is now determined by a fourth-rank tensor. Generalized expressions for the Leverett and relative phase permeability
functions are given for orthotropic and transversely isotropic media with account for the hysteresis of the phase permeabilities
and capillary pressure. 相似文献
7.
A method has been developed for investigating the relative permeabilities of porous media for oil and for aqueous solutions of polymers; experimental equipment has been developed for determining the phase permeabilities by a stationary method. Investigations were made of the influence of polyacrylamide additives on the change in the relative permeabilities for the simultaneous flow of water and a nonpolar hydrocarbon liquid. It was established that addition of the polymer can lead to a simultaneous reduction in the relative permeability for the wetting liquid and an increase for the nonwetting liquid. The phase permeabilities were obtained for oil and water moving behind a fringe of polymer substance. It was established that the phase permeability for the water phase is a function of the saturation and the amount of sorbate. A cycle of experimental investigations was made into the influence of the rate of pumping and the concentration of the dissolved polymer on the change in the relative permeabilities.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 163–167, July–August, 1980. 相似文献
8.
Adding surfactant into the displacing aqueous phase during surfactant-enhanced aquifer remediation of NAPL contamination and
in chemical flooding oil recovery significantly changes interfacial tension (IFT) (σ) on water–oil interfaces within porous
media. The change in IFT may have a large impact on relative permeability for the two-phase flow system. In most subsurface
flow investigations, however, the influence of IFT on relative permeability has been ignored. In this article, we present
an experimental study of two-phase relative- permeability behavior in the low and more realistic ranges of IFT for water–oil
systems. The experimental work overcomes the limitations of the existing laboratory measurements of relative permeability
(which are applicable only for high ranges of IFT (e.g., σ > 10−2 mN/m). In particular, we have (1) developed an improved steady-state method of measuring complete water–oil relative permeability
curves; (2) proven that a certain critical range of IFT exists such that IFT has little impact on relative permeability for
σ greater than this range, while within the range, relative permeabilities to both water and oil phases will increase with
decreasing IFT; and (3) shown that a functional correlation exists between water–oil two-phase relative permeability and IFT.
In addition, this work presents such correlation formula between water–oil two-phase relative permeability and IFT. The experimental
results and proposed conceptual models will be useful for quantitative studies of surfactant-enhanced aquifer remediation
and chemical flooding operations in reservoirs. 相似文献
9.
The problem of convective instability of a fluid in a system consisting of two horizontal porous strata with different permeabilities
and a permeable common boundary is considered. The problem is investigated in parametric form as a function of the stratum
thickness ratio and stratum permeabilities. As distinct from a uniform stratum, in this case the neutral curve can have one
or two minima depending on the relationship between the parameters. The case of two minima is characterized by the condition
of loss of stability of the fluid in the system as a whole and in the thinner stratum with greater permeability. These minima
correspond to significantly different wave numbers.
Makhachkala. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 165–169, January–February,
1999. 相似文献
10.
Finite Element-Based Characterization of Pore-Scale Geometry and Its Impact on Fluid Flow 总被引:1,自引:0,他引:1
We present a finite element (FEM) simulation method for pore geometry fluid flow. Within the pore space, we solve the single-phase
Reynold’s lubrication equation—a simplified form of the incompressible Navier–Stokes equation yielding the velocity field
in a two-step solution approach. (1) Laplace’s equation is solved with homogeneous boundary conditions and a right-hand source
term, (2) pore pressure is computed, and the velocity field obtained for no slip conditions at the grain boundaries. From
the computed velocity field, we estimate the effective permeability of porous media samples characterized by section micrographs
or micro-CT scans. This two-step process is much simpler than solving the full Navier–Stokes equation and, therefore, provides
the opportunity to study pore geometries with hundreds of thousands of pores in a computationally more cost effective manner
than solving the full Navier–Stokes’ equation. Given the realistic laminar flow field, dispersion in the medium can also be
estimated. Our numerical model is verified with an analytical solution and validated on two 2D micro-CT scans from samples,
the permeabilities, and porosities of which were pre-determined in laboratory experiments. Comparisons were also made with
published experimental, approximate, and exact permeability data. With the future aim to simulate multiphase flow within the
pore space, we also compute the radii and derive capillary pressure from the Young–Laplace’s equation. This permits the determination
of model parameters for the classical Brooks–Corey and van-Genuchten models, so that relative permeabilities can be estimated. 相似文献
11.
N. V. Bondarenko 《Fluid Dynamics》1981,16(4):554-559
The approach proposed by Podil'chuk [1] is used to derive a system of equations of motion for saturated porous media, allowance being made for the mutual influence of the solid, liquid, and gas phases. The permeabilities of the anisotropic porous medium are assumed to depend on the direction. It is shown that when there are no gas phases and the liquid is incompressible the system of equations reduces to the general equations of the theory of elasticity of an anisotropic body with fictitious stress components. For a porous medium saturated with liquid, the relationships between the permeabilities and the anisotropy constants are obtained. The motion of liquid in an elastic porous medium in the form of an orthotropic cylindrical region with a cavity in the form of a circular cylinder is considered as an example.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 82–87, July–August, 1981. 相似文献
12.
M. N. Dmitriev N. M. Dmitriev V. V. Kadet M. N. Kravchenko S. G. Rassokhin 《Fluid Dynamics》2004,39(4):589-593
The results of an experimental determination of the relative phase permeabilities during flow of two immiscible fluids in stratified sandstone with transversally isotropic characteristics are presented. The measurements were performed on samples oriented in three directions: along, perpendicular to and at an angle of 45° to the stratification plane. An approximate solution of the problem of steady two-phase flow toward a finite gallery in an anisotropic porous medium for arbitrary relative orientation of the gallery and the principal axes of the absolute permeability tensor is given. This solution was tested against the experimental results. The good agreement between the theoretical and experimental results makes it possible to recommend for engineering calculations both the relations between the absolute and phase permeabilities for transversally isotropic and orthotropic porous media and the approximate solution obtained. 相似文献
13.
R. A. Valiullin R. F. Sharafutdinov A. A. Sadretdinov A. S. Bochkov 《Journal of Applied Mechanics and Technical Physics》2008,49(6):992-997
The distributions of phase saturations, pressure, and temperature in a porous medium of nonuniform permeability are studied
by numerical modeling of nonisothermal two-phase filtration of oil and water with the Joule-Thomson effect and adiabatic effect
taken into account. It is shown that the presence of nonuniformity in the near-well zone of the reservoir results in nonmonotonic
angular and radial distributions of temperature and phase saturations. During oil and water filtration, there is transition
from negative to positive temperature anomalies or vice versa, depending on the ratio of the reservoir permeabilities and
the presence of a segment on which the angular temperature distribution in the well is nonuniform.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 6, pp. 124–130, November–December, 2008. 相似文献
14.
The most general representation of the functions of the relative phase permeabilities for porous media is written explicitly. The relations proposed for the relative phase permeabilities generalize those obtained earlier for media with transversely-isotropic and orthotropic percolation properties [1, 2] which can now be obtained as a particular case. A laboratory measurement technique for finding the percolation properties and determining the absolute and phase permeabilities for media with different types of anisotropy is discussed.__________Translated from Izvestiya Rossiiskoi Academii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, 2005, pp. 118–125.Original Russian Text Copyright © 2005 by Dmitriev, Dmitriev, and Maksimov. 相似文献
15.
Calculating the Anisotropic Permeability of Porous Media Using the Lattice Boltzmann Method and X-ray Computed Tomography 总被引:1,自引:0,他引:1
Yuan Gao Xiaoxian Zhang Pratap Rama Ying Liu Rui Chen Hossein Ostadi Kyle Jiang 《Transport in Porous Media》2012,92(2):457-472
A lattice Boltzmann (LB) method is developed in this article in a combination with X-ray computed tomography to simulate fluid
flow at pore scale in order to calculate the anisotropic permeability of porous media. The binary 3D structures of porous
materials were acquired by X-ray computed tomography at a resolution of a few microns, and the reconstructed 3D porous structures
were then combined with the LB model to calculate their permeability tensor based on the simulated velocity field at pore
scale. The flow is driven by pressure gradients imposed in different directions. Two porous media, one gas diffusion porous
layer used in fuel cells industry and glass beads, were simulated. For both media, we investigated the relationship between
their anisotropic permeability and porosity. The results indicate that the LB model is efficient to simulate pore-scale flow
in porous media, and capable of giving a good estimate of the anisotropic permeability for both media. The calculated permeability
is in good agreement with the measured date; the relationship between the permeability and porosity for the two media is well
described by the Kozeny–Carman equation. For the gas diffusion layer, the simulated results showed that its permeability in
one direction could be one order of magnitude higher than those in other two directions. The simulation was based on the single-relaxation
time LB model, and we showed that by properly choosing the relaxation time, it could give similar results to those obtained
using the multiple-relaxation time (MRT) LB method, but with only one third of the computational costs of MRTLB model. 相似文献
16.
S. E. Kholodovskii 《Fluid Dynamics》1993,28(5):739-740
A method is proposed for constructing homogeneous anisotropic models of new classes of highly inhomogeneous nondeformable porous media consisting of arbitrarily oriented systems of layers representing fractures and impermeable barriers (screens) embedded in each other with an arbitrary depth of embedment. It is assumed that the permeability functions of the elementary cells of the media can be represented in some Cartesian coordinate system (proper to each cell) in the form of a product of three integrable functions that depend on the corresponding coordinates. As distinct from known methods of averaging differential operators, the method in question is based on porous media flow considerations and reduces to replacing the highly inhomogeneous soils with homogeneous anistropic soils, so that on the boundaries of the domain considered the basic flow parameters remain the same.Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika, Zhidkosti i Gaza, No. 5, pp. 190–192, September–October, 1993. 相似文献
17.
Two phase countercurrent steady-state flow through permeable media in one dimension is discussed. For steady-state countercurrent flow in water wet porous media, a saturation profile is predicted with the water saturation decreasing in the direction that the water phase is flowing. The de la Cruz and Spanos equations predict that the Muskat relative permeability curves for countercurrent flow will be less than the Muskat relative permeability curves for steady-state cocurrent flow. This result has immediate implications regarding the use of external drive techniques to determine relative permeabilities based on the Buckley-Leverett theory and Muskat's equations. These equations and current experimental evidence involving countercurrent flow indicate that Muskat's equations do not adequately describe the multiphase flow of immiscible fluids. 相似文献
18.
The lattice Boltzmann method (LBM) is used to simulate the flow through an idealized proton exchange membrane fuel cell (PEMFC) porous transport layer (PTL) geometry generated using a Monte Carlo method. Using the calculated flow field, Darcy's law is applied and the permeability is calculated. This process is applied in both through‐ and in‐plane directions of the paper as both of these permeability values are important in computational fluid dynamics models of PEMFCs. It is shown that the LBM can be used to determine permeability in a random porous media by solving the flow in the microstructure of the material. The permeability in the through‐ and in‐plane directions is shown to be different and the anisotropic nature of the geometry creates anisotropic permeability. It is also found that fiber arrangement plays a large role in the permeability of the PTL. New correlations are presented for in‐ and though‐plane permeabilities of fibrous porous media with (0.6<ε<0.8). Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
19.
For two-phase immiscible fluid flows a generalized Darcy's law is written in invariant tensor form for crystallographic point symmetry groups and anisotropic textures. The representation of the phase permeability coefficient tensors and the structure of the expressions for the relative phase permeabilities are analyzed for all symmetry groups. The relation between the phase and absolute permeability coefficient tensors is specified by a fourth-rank tensor with the external symmetry coinciding with external symmetry of the phase permeability tensors. It is shown that the external symmetry of the phase permeability coefficient tensors can differ from the external symmetry of the absolute permeability tensor. For triclinic and monoclinic symmetry groups it is shown that the phase permeability coefficient tensors may not be coaxial with each other and with the absolute permeability tensor; moreover, the directions of the principal axes of the phase permeability coefficient tensors can depend on the saturation. 相似文献
20.
Two-phase flow through a medium with two porosities in which the absolute permeabilities and the capillary pressure functions
of the components differ by an order of magnitude is investigated. A classification and diagram of the elementary flows are
proposed at the single cell level. An averaged model is developed for a single class of systems in which source-type capillary-dispersion
flow predominates in the blocks. This model contains a nonlinear kinetic relation between the average values of the capillary
pressure functions. An expansion of the effective phase permeability tensor allowing it to be calculated efficiently is proposed.
The capillary relaxation time is explicitly determined. Examples of calculations of the averaged phase permeability tensor
and the capillary relaxation time are given.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, pp. 93–103, May–June, 1998.
The work was carried out with the support from the Russian Foundation for Basic Research (project No. 95-01-01179a). 相似文献