共查询到20条相似文献,搜索用时 31 毫秒
1.
Maria J. Martín-Alfonso Francisco Martínez-Boza Pedro Partal Crispulo Gallegos 《Rheologica Acta》2006,45(4):357-365
Transportation and consumption of petroleum products around the world have created a potential risk for oil spills in the environment. Knowledge of high-pressure rheological behaviour of heavy crude oil fractions, which are usually transported in oil tankers, is very important to design deep recovering operations of the oil remaining in the tanks after an accident. The effect of pressure on the viscosity of these materials is not well understood, this is mainly due to experimental constraints involving high-pressure rheology measurements at low shear rates. Consequently, the overall objective of this work is to model the temperature–pressure–viscosity dependence of a selected heavy fuel oil in a wide range of pressure and temperature. With this aim, viscous flow tests at different temperatures and differential pressures and modulated differential scanning calorimetry tests were carried out on the heavy fuel oil selected. A temperature–pressure–viscosity model (FMT model) fits fairly well the experimental results obtained in the whole differential pressure range studied. However, viscosity values at temperatures lower than 10°C cannot be predicted due to microstructural changes associated with the solidification process of the heaviest components of the fuel oil tested.Paper presented at the European Rheology Conference (AERC) held in Grenoble, France, April 21–23, 2005. 相似文献
2.
In this article, the numerical simulations for one-dimensional three-phase flows in fractured porous media are implemented.
The simulation results show that oil displacement in matrix is dominated by oil–water capillary pressure only under certain
conditions. When conditions are changed to decrease the amount of water entering into the fractured media from the boundary
of the flow field, water in fracture may be vaporized to superheated steam. In these cases, the appearance of superheated
steam in fracture rather than in matrix will decrease the fracture pressure and generate the pressure difference between matrix
and fracture, which results in oil flowing from matrix to fracture. Assuming that oil is wetting to steam, the matrix steam–oil
capillary pressure will decrease the matrix oil-phase pressure as the matrix steam saturation increases. After the steam–oil
capillary pressure finally exceeds the pressure difference due to the appearance of superheated steam in fracture, the oil
displacement in matrix will stop. It is also shown that variations of the water relative permeability curve in matrix do not
result in different mechanisms for oil displacement in matrix. The simulation results suggest that the amount of liquid water
supply from the boundary of flow field fundamentally influence the mechanisms for oil displacement in matrix. 相似文献
3.
A. Yu. D’yachenko V. I. Terekhov N. I. Yarygina 《Journal of Applied Mechanics and Technical Physics》2006,47(5):671-678
The process of vortex formation in a cavity with inclined walls, which has a moderate aspect ratio, is experimentally studied,
and the distribution of pressure coefficients is measured. The angle of inclination of the side walls ϕ is varied from 30
to 90°. It is found that the flow in the cavity becomes unstable in the range of inclination angles ϕ = 60–70°. Flow reconstruction
occurs, which substantially alters the surface-temperature and static-pressure distributions. Large changes in these characteristics
and their nonuniform distributions for these angles are observed across the cavity on its frontal wall and on the bottom.
For small angles (ϕ = 30 and 45°), the pressure on the rear wall drastically increases, which leads to a small increase in
pressure averaged over the entire cavity surface.
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Translated from PrikladnayaMekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 5, pp. 68–76, September–October, 2006. 相似文献
4.
Hydrodynamic analysis of the displacement conditions of formation fluids using an axisymmetric model
I. B. Chernoshchuk 《Journal of Applied Mechanics and Technical Physics》2008,49(2):201-208
The axisymmetric problem of the displacement of formation fluids by a drilling mud filtrate with filter cake formation is
considered. An analysis is made of the distribution and variation of the main parameters of the process: filtrate volume,
filter cake thickness, oil saturation, and pressure. The positions of the water-saturation and salt-concentration fronts are
determined. The results are compared with the geophysical logging data for straight-hole drilling.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 2, pp. 56–64, March–April, 2008. 相似文献
5.
A. D. Zaikin 《Journal of Applied Mechanics and Technical Physics》2000,41(1):139-148
The influence of the surface roughness on the stress state of a rock is studied. For an elastic half-plane in the gravity
field that contains a notch shaped like a semicircle, the stress distribution is constructed. It is shown that depending on
the Poisson ratio, the notch bottom can be in a state of tension or compression. The polynomial dependence of pressure on
depth is given on the axis of symmetry.
Novosibirsk State University, Novosibirsk 630090. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 41,
No. 1, pp. 152–161, January–February, 2000. 相似文献
6.
An experimental investigation was carried out on mobilization and very slow flow of oil slugs in a capillary tube. The pressure
drop of the slug flow was measured at every stage of mobilizing and moving the oil slugs as a function of capillary number
in the range of 4 × 10−7–6 × 10−6. The pressure drop across the oil slug experienced three stages: build-up, hold-up, and steady stages. During the build-up
stage, the convex rear end of the slug was becoming concave into the oil slug and the convex front end of the slug moved ahead
to form a new portion of the slug. At the hold-up stage, both the concave rear end and the front end continued to advance,
and the initial contact line of the oil slug with the tube wall through a very thin water film was being shortened. At this
stage, the pressure drop reached a maximum value and remained nearly constant. At the steady stage, after the oil slug was
completely mobilized out of the original contact region, the differential pressure had a step-drop first, and then the oil
slug flowed at a lower differential pressure depending on the flow rate. Numerous slug flow tests of this study showed that
the hold-up pressure drop was always higher than the steady stage pressure drop. Results also showed that the measured extra
pressure drop was significantly high compared to the pressure drop calculated from Poiseuille equation, which is still commonly
used in network modeling of multiphase flow in porous media. 相似文献
7.
L. A. Nazarov L. A. Nazarova V. M. Fomin N. P. Ryashentsev A. N. Ryashentsev A. V. Solov'ev 《Journal of Applied Mechanics and Technical Physics》2006,47(1):109-115
A laboratory study including physical modeling of filtration processes in porous beds with similarity criteria satisfied is
performed. It is demonstrated that weak dynamic actions on stressed host rock blocks can initiate repacking of the system
of blocks, leading to an increase in pressure in the productive bed and in oil recovery.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 1, pp. 131–138, January–February, 2006. 相似文献
8.
Mohammadhossein Heidari Sureshjani Shahab Gerami Mohammad Ali Emadi 《Transport in Porous Media》2012,93(1):147-169
One of the widely used methods for modeling matrix–fracture fluid exchange in naturally fractured reservoirs is dual porosity
approach. In this type of modeling, matrix blocks are regarded as sources/sinks in the fracture network medium. The rate of
fluid transfer from matrix blocks into fracture medium may be modeled using shape factor concept (Warren and Root, SPEJ 3:245–255,
1963); or the rate–time solution is directly derived for the specific matrix geometry (de Swaan, SPEJ 16:117–122, 1976). Numerous works have been conducted to study matrix–fracture fluid exchange for slightly compressible fluids (e.g. oil).
However, little attention has been taken to systems containing gas (compressible fluid). The objective of this work is to
develop explicit rate–time solutions for matrix–fracture fluid transfer in systems containing single phase gas. For this purpose,
the governing equation describing flow of gas from matrix block into fracture system is linearized using pseudopressure and
pseudotime functions. Then, the governing equation is solved under specific boundary conditions to obtain an implicit relation
between rate and time. Since rate calculations using such an implicit relation need iterations, which may be computationally
inconvenient, an explicit rate–time relation is developed with the aid of material balance equation and several specific assumptions.
Also, expressions are derived for average pseudopressure in matrix block. Furthermore, simplified solutions (originated from
the complex general solutions) are introduced applicable in infinite and finite acting flow periods in matrix. Based on the
derived solutions, expressions are developed for shape factor. An important observation is that the shape factor for gas systems
is the same as that of oil bearing matrix blocks. Subsequently, a multiplier is introduced which relates rate to matrix pressure
instead of matrix pseudopressure. Finally, the introduced equations are verified using a numerical simulator. 相似文献
9.
Based on a modified Darcy–Brinkman–Maxwell model, a linear stability analysis of a Maxwell fluid in a horizontal porous layer
heated from below by a constant flux is carried out. The non-oscillatory instability and oscillatory instability with different
hydrodynamic boundaries such as rigid and free surfaces at the bottom are studied. Compared with the rigid surface cases,
onset of fluid motion due to non-oscillatory instability and oscillatory instability is found to occur both more easily for
the system with a free bottom surface. The critical Rayleigh number for onset of fluid motion due to non-oscillatory instability
is lower with a constant flux heating bottom than with an isothermal heating bottom, but the result due to oscillatory instability
is in contrast. The effects of the Darcy number, the relaxation time, and the Prandtl number on the critical Rayleigh number
are also discussed. 相似文献
10.
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.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 6, pp. 124–130, November–December, 2008. 相似文献
11.
Akihide Kaizawa Nobuhiro Maruoka Atsushi Kawai Hiroomi Kamano Tetsuji Jozuka Takeshi Senda Tomohiro Akiyama 《Heat and Mass Transfer》2008,44(7):763-769
A waste heat transportation system––trans-heat (TH) system––is quite attractive that uses the latent heat of a phase change
material (PCM). The purpose of this paper is to study the thermophysical properties of various sugars and sodium acetate trihydrate
(SAT) as PCMs for a practical TH system and the heat transfer property between PCM selected and heat transfer oil, by using
differential scanning calorimetry (DSC), thermogravimetry-differential thermal analysis (TG-DTA) and a heat storage tube.
As a result, erythritol, with a large latent heat of 344 kJ/kg at melting point of 117°C, high decomposition point of 160°C
and excellent chemical stability under repeated phase change cycles was found to be the best PCM among them for the practical
TH system. In the heat release experiments between liquid erythritol and flowing cold oil, we observed foaming phenomena of
encapsulated oil, in which oil droplet was coated by solidification of PCM. 相似文献
12.
The interacting capillary bundle model proposed by Dong et al. [Dong, M., Dullien, F.A.L., Zhou, J.: Trans. Porous Media 31, 213–237 (1998); Dong, M., Dullien, F.A.L., Dai, L., Li, D.: Trans. Porous Media 59, 1–18 (2005); Dong, M., Dullien, F.A.L., Dai, L., Li, D.: Trans. Porous Media 63, 289–304 (2006)] has simulated correctly various aspects of immiscible displacement in porous media, such as oil production
histories at different viscosity ratios, the effects of water injection rate and of the oil–water viscosity ratio on the shape
of the displacement front and the independence of relative permeabilities of the viscosity ratio. In the interacting capillary
bundle model pressure equilibrium was assumed at any distance x measured along the bundle. Interaction between the capillaries also results in transfer of fluids across the capillaries.
In the first part of this paper the process of fluid transfer between two capillaries is analysed and an algebraic expression
for this flow is derived. Consistency with the assumption of pressure equilibration requires that all transfer must take place
at the positions of the oil/water menisci in the tubes without any pressure drop. It is shown that fluid transfer between
the tubes has no effect on the predictions obtained with the model. In the second part of the paper the interacting tube bundle
model is made more realistic by assuming fluid transfer between the tubes all along the single phase flow regions across a
uniform resistance, resulting in pressure differences throughout the single phase regions between the fluids present in the
different tubes. The results of numerical simulations obtained with this improved interacting capillary bundle model show
only small differences in the positions of the displacement front as compared with the predictions of the idealized model. 相似文献
13.
The head-on collision of a combustion front with a closely packed bed of ceramic-oxide spheres was investigated in a vertical
76.2 mm diameter tube containing a nitrogen diluted stoichiometric ethylene–oxygen mixture. A layer of spherical beads in
the diameter range of 3–12.7 mm was placed at the bottom of the tube and a flame was ignited at the top endplate. Four orifice
plates spaced at one tube diameter were placed at the ignition end of the tube in order to accelerate the flame to either
a “fast-flame” or a detonation wave before the bead layer face. The mixture reactivity was adjusted by varying the initial
mixture pressure between 10 and 100 kPa absolute. The pressure before and within the bead layer was measured by flush wall-mounted
pressure transducers. For initial pressures where a fast-flame interacts with the bead layer peak pressures recorded at the
bead layer face were as high as five times the reflected Chapman–Jouget detonation pressure. The explosion resulting from
the interaction developed by two distinct mechanisms; one due to the shock reflection off the bead layer face, and the other
due to shock transmission and mixing of burned and unburned gas inside the bead layer. The measured explosion delay time (time
after shock reflection from the bead layer face) was found to be independent of the incident shock velocity. As a result,
the explosion initiation is not the direct result of the shock reflection process but instead is more likely due to the interaction
of the reflected shock wave and the trailing flame. The bead layer was found to be very effective in attenuating the explosion
front transmitted through the bead layer and thus isolating the tube endplate.
This paper is based on work that was presented at the 21th International Colloquium on the Dynamics of Explosions and Reactive
Systems, Poitiers, France, July 23–27, 2007. 相似文献
14.
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
15.
A numerical study is performed to analyze steady laminar forced convection in a channel in which discrete heat sources covered
with porous material are placed on the bottom wall. Hydrodynamic and heat transfer results are reported. The flow in the porous
medium is modeled using the Darcy–Brinkman–Forchheimer model. A computer program based on control volume method with appropriate
averaging for diffusion coefficient is developed to solve the coupling between solid, fluid, and porous region. The effects
of parameters such as Reynolds number, Prandtl number, inertia coefficient, and thermal conductivity ratio are considered.
The results reveal that the porous cover with high thermal conductivity enhances the heat transfer from the solid blocks significantly
and decreases the maximum temperature on the heated solid blocks. The mean Nusselt number increases with increase of Reynolds
number and Prandtl number, and decrease of inertia coefficient. The pressure drop along the channel increases rapidly with
the increase of Reynolds number. 相似文献
16.
Kh. M. Gamzaev 《Journal of Applied Mechanics and Technical Physics》2009,50(3):466-469
The spread of an oil slick in the sea is considered. A mathematical model of the process is proposed and a formulas for determining
the oil slick sizes in explicit form are obtained.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 50, No. 3, pp. 127–130, May–June, 2009. 相似文献
17.
18.
Victor N. Nikolaevskiy 《Transport in Porous Media》2008,73(2):125-140
The Frenkel–Biot P-wave of the first type is a seismic longitudinal wave observed in rocks fully saturated with oil, water
or high-pressure gas. The P-wave of the second type is observed in unsaturated soils and other porous media saturated with
gas of low pressure. Their models include properties of the skeleton, that is, its elastic modules and its own viscosity.
If the non-linear terms are accounted for, the asymptotic analysis, usual for weak non-linear waves, might be applied to get
the wave spectrum evolution. The wetness of grains contacts in soils and such components of oil as tars or bitumen, which
attached to the skeleton, can be described by generalized viscous–elastic stress–strain connections. The latter are nominated
in such a way that creates the narrow frequency interval of wave of negative dissipation where the non-linear terms begin
to play the main role besides the neutral stability for waves of zero wave number. The corresponding case, relevant to single
continuum model, was analyzed in the literature. Here it is shown that the interpenetrating continua with interaction of the
Darcy type provide the dissipation sink in the wave evolution equation. This generalization, (Tribelsky, M.I.: Phys. Rev.
Lett. (2007, submitted)), can stabilize the asymptotic solution of the evolution equation, where the dispersion terms are
omitted. The asymptotic solution of the equation is invariant to initial conditions and it means a transformation of initial
wave spectra to unique one while wave is spreading in the viscous–elastic medium under consideration. This explains the phenomenon,
observed in wave tests at marine beach, when any dynamics action (impact, explosion, and ultrasound action) created at some
distance a wave of a single frequency (~25 Hz). 相似文献
19.
The characteristics of the flow and heat transfer in two- and three-dimensional open cavities on plane and cylindrical surfaces
in a supersonic stream in the presence of a turbulent boundary layer have been investigated experimentally. The effects of
the Mach number, boundary layer thickness, the shape of the cavity, and its angle of inclination to the free-stream direction
on the flow parameters in the mixing layer above the cavity and the heat flux and pressure distribution on the surface of
the cavity and its bottom are descirbed.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 74–80, July–August, 1998. 相似文献
20.
The problem of the onset of convective roll instabilities in a horizontal porous layer with isothermal boundaries at unequal
temperatures, well known as the Horton–Rogers–Lapwood problem, is revisited including the effect of pressure work and viscous
dissipation in the local energy balance. A linear stability analysis of rolls disturbances is performed. The analysis shows
that, while the contribution of viscous dissipation is ineffective, the contribution of the pressure work may be important.
The condition of marginal stability is investigated by adopting two solution procedures: method of weighted residuals and
explicit Runge–Kutta method. The pressure work term in the energy balance yields an increase of the value of the Darcy–Rayleigh
number at marginal stability. In other words, the effect of pressure work is a stabilizing one. Furthermore, while the critical
value of the Darcy– Rayleigh number may be considerably affected by the pressure work contribution, the critical value of
the wave number is affected only in rather extreme cases, i.e. for very high values of the Gebhart number. A nonlinear stability
analysis is also performed pointing out that the joint effects of viscous dissipation and pressure work result in a reduction
of the excess Nusselt number due to convection, when the Darcy–Rayleigh number is replaced by the superadiabatic Darcy–Rayleigh
number. 相似文献