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1.
Steady flow of homogeneous fluid in an oil reservoir recovery element with a hydrofracture 总被引:1,自引:0,他引:1
The plane problem of steady flow of a homogeneous fluid in a five-point oil reservoir recovery element with a hydrofracture
of finite conductivity is considered. It is assumed that the motion of the fluid in the reservoir and in the fracture obeys
a linear resistance law and that the permeability of the reservoir and the effective permeability of the fracture are sharply
different. Analytic solutions are obtained for the case of an ideal fracture (fracture of infinite conductivity). The flows
are analyzed numerically with allowance for the finite conductivity of the fracture.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.1, pp. 104–112, January–February,
1994. 相似文献
2.
A numerical investigation of the steady-state, laminar, axi-symmetric, mixed convection heat transfer in the annulus between
two concentric vertical cylinders using porous inserts is carried out. The inner cylinder is subjected to constant heat flux
and the outer cylinder is insulated. A finite volume code is used to numerically solve the sets of governing equations. The
Darcy–Brinkman–Forchheimer model along with Boussinesq approximation is used to solve the flow in the porous region. The Navier–Stokes
equation is used to describe the flow in the clear flow region. The dependence of the average Nusselt number on several flow
and geometric parameters is investigated. These include: convective parameter, λ, Darcy number, Da, thermal conductivity ratio,
K
r, and porous-insert thickness to gap ratio (H/D). It is found that, in general, the heat transfer enhances by the presence of porous layers of high thermal conductivity
ratios. It is also found that there is a critical thermal conductivity ratio on which if the values of Kr are higher than
the critical value the average Nusselt number starts to decrease. Also, it found that at low thermal conductivity ratio (K
r ≈ 1) and for all values of λ the porous material acts as thermal insulation. 相似文献
3.
The problem of gas-condensate flow in the vicinity of a production well with a hydraulic fracture is considered. In the matrix,
the flow is assumed to be three-dimensional, and at the fracture, it is assumed to be two-dimensional. It is shown that, for
steady-state flow, the problem is split into a physicochemical problem (of phase transitions) and a filtration problem (of
determining the pressure field). Numerical solutions are constructed for a rectangular fracture with finite and infinite conductivities.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 3, pp. 128–136, May–June, 2008. 相似文献
4.
This study reports an investigation on the characteristics of single-phase (brine) and two-phase (DNAPL–brine) flows in induced
fractures. The fracture aperture and fluid phase distributions were determined using X-ray computer tomography. In the single-phase
flow tests, the pressure gradient across the induced fractures increases linearly with increasing flow rate. However, models
based on the measured aperture do not yield a consistent match with the experimental data because the effect of pressure losses
due to aperture variation and undulation are not taken into account. In the two-phase flow tests, the measured phase distributions
reveal that the flow pattern is dominated by a dispersed or mixed flow in which either DNAPL or brine phase is discontinuous.
The channel flow pattern, in which DNAPL and brine phases are continuous in the fracture and well represented by the widely
used Romm’s relative permeability relationship was not observed in this study. In contrast, a Lockhart–Martinelli-type correlation
developed for gas–liquid flow in pipes was found to match the pressure gradient and phase saturation results obtained from
the laboratory tests. 相似文献
5.
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
6.
裂隙岩体渗透系数以及渗透主方向的确定对研究岩体渗透性大小及各向异性具有重要意义。高放废物地质处置库介质岩体的渗透性能将直接影响其使用安全性。本文运用离散裂隙网络模拟的方法对我国高放废物处置库甘肃北山预选区3#钻孔附近裂隙岩体进行了渗透性质分析。通过对3#钻孔1715~1780m段压水试验数据的反演,标定了离散裂隙网络渗流模型中的裂隙渗透参数(导水系数T)。利用标定的离散裂隙网络模型对场区裂隙岩体进行了渗流模拟,确定了该区域裂隙岩体的渗流表征单元体(REV)的尺寸大小以及渗透主值和主渗透方向。运用离散裂隙网络模型计算得出的渗透主值的几何均值与现场压水试验计算结果较接近,证明了计算结果的有效性。 相似文献
7.
A method of calculating the conductivity of capillary networks which combines percolation concepts of conductivity in the
neighborhood of the flow threshold with the results obtained using the effective medium model is proposed. The conductivity
calculated theoretically is compared with experimental data. Water and oil phase permeabilities for combined flow through
a capillary network are determined as an example of the use of the relations obtained.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 79–83, January–February,
2000. 相似文献
8.
In this study, a steady, fully developed laminar forced convection heat augmentation via porous fins in isothermal parallel-plate
duct is numerically investigated. High-thermal conductivity porous fins are attached to the inner walls of two parallel-plate
channels to enhance the heat transfer characteristics of the flow under consideration. The Darcy–Brinkman–Forchheimer model
is used to model the flow inside the porous fins. This study reports the effect of several operating parameters on the flow
hydrodynamics and thermal characteristics. This study demonstrates, mainly, the effects of porous fin thickness, Darcy number,
thermal conductivity ratio, Reynolds number, and microscopic inertial coefficient on the thermal performance of the present
flow. It is found that the highest Nusselt number is achieved at fully filled porous duct which requires the highest pumping
pressure. The results show that using porous fins requires less pumping pressure with comparable high heat augmentation weight
against fully filled porous duct. It is found that higher Nusselt numbers are achieved by increasing the microscopic inertial
coefficient (A), the Reynolds number (Re), and the thermal conductivity of the porous substrate k
2. The results show that heat transfer can be enhanced (1) with the use of high thermal conductivity fins, (2) by decreasing
the Darcy number, and (3) by increasing microscopic inertial coefficient. 相似文献
9.
Mohamed Abd El-Aziz 《Meccanica》2007,42(4):375-386
An analysis has been carried out to obtain the flow, heat and mass transfer characteristics of a viscous electrically conducting
fluid having temperature dependent viscosity and thermal conductivity past a continuously stretching surface, taking into
account the effect of Ohmic heating. The flow is subjected to a uniform transverse magnetic field normal to the plate. The
resulting governing three-dimensional equations are transformed using suitable three-dimensional transformations and then
solved numerically by using fifth order Runge–Kutta–Fehlberg scheme with a modified version of the Newton–Raphson shooting
method. Favorable comparisons with previously published work are obtained. The effects of the various parameters such as magnetic
parameter M, the viscosity/temperature parameter θ
r
, the thermal conductivity parameter S and the Eckert number Ec on the velocity, temperature, and concentration profiles, as well as the local skin-friction coefficient, local Nusselt number,
and the local Sherwood number are presented graphically and in tabulated form. 相似文献
10.
Molecular dynamics simulation of annular flow boiling in a nanochannel is numerically investigated. In this research, an annular
flow model is developed to predict the superheated flow boiling heat transfer characteristics in a nanochannel. To characterize
the forced annular boiling flow in a nanochannel, an external driving force
F?\textext \overrightarrow {F}_{\text{ext}} ranging from 1 to 12 PN (PN = pico newton) is applied along the flow direction to inlet fluid particles during the simulation.
Based on an annular flow model analysis, it is found that saturation condition and superheat degree have great influences
on the liquid–vapor interface. Also, the results show that due to the relatively strong influence of the surface tension in
small channels, the interface between the liquid film and the vapor core is fairly smooth, and the mean velocity along the
stream-wise direction does not change anymore. Also, it is found that the heat flux values depend on the boundary conditions.
Finally, the Green–Kubo formula is used to calculate the thermal conductivity of liquid Argon. The simulations predict thermal
conductivity of liquid Argon quite well. 相似文献
11.
Hadi Saboorian-Jooybari Siavash Ashoori Gholamhossein Mowazi 《Transport in Porous Media》2012,92(3):687-708
In dual porosity modeling of naturally fractured reservoirs, fluids exchange between the high porous matrix blocks and high
permeable fracture systems is governed by transfer function. Therefore, transfer function, and specially shape factor as the
main part of it, control fluids flow behavior, which certainly have significant effects on development and management plan
of naturally fractured reservoirs. Also several formulations have been proposed for shape factor by a number of researchers,
nearly all of them derived for expansion mechanism. But, shape factor is a phase sensitive parameter that can greatly affect
results of simulation. Moreover, several shortcomings are inherent in the derived expressions of shape factor for imbibition
process. The main aim of this work is to develop a new time-dependent matrix–fracture shape factor specific to countercurrent
imbibition. In this study, fluid saturation distribution within a matrix block is analytically derived by solving capillary–diffusion
equation under different imposed boundary conditions for the process where countercurrent imbibition is the dominant oil drive
mechanism. The validity of the solutions is checked against literature experimental data (Bourbiaux and Kalaydjian, SPERE
5, 361–368, SPE 18283, 1990) and also by performing single porosity fine grid simulations. Then, the concept of analogy between the transport phenomena
is employed to propose a new expression for matrix–fracture transfer function that is used to derive transient shape factor.
It is illustrated in this article that time variation of imbibtion rate and shape factor can be used to diagnose different
states of imbibition process. Although, the displacement process and employed approaches are completely different in this
and other studies (Chang, Technical report, 1993; Kazemi and Gilman (eds.) Flow and contaminant transport in fractured rock. Academic Press, San Dieg, 1993; Zimmerman et al., Water Resour Res, 29, 2127–2137, 1993; Lim and Aziz, J Pet Sci Eng 13, 169–178, 1995), but we arrived at the consistent values of shape factor under limiting condition of pseudo steady state flow. This means
that after establishment of pseudo steady state, shape factor is only controlled by matrix geometry regardless of the displacement
process, i.e., expansion or imbibition mechanism, However, shape factor is completely phase sensitive and process dependent
during unsteady and late-transient states. Finally, boundary condition dependency of shape factor is investigated. 相似文献
12.
Numerical simulation of blood flow and interstitial fluid pressure in solid tumor microcirculation based on tumor-induced angiogenesis 总被引:1,自引:0,他引:1
Gaiping Zhao Jie Wu Shixiong Xu M. W. Collins Quan Long Carola S. König Yuping Jiang Jian Wang A. R. Padhani 《Acta Mechanica Sinica》2007,23(5):477-483
A coupled intravascular–transvascular–interstitial fluid flow model is developed to study the distributions of blood flow
and interstitial fluid pressure in solid tumor microcirculation based on a tumor-induced microvascular network. This is generated
from a 2D nine-point discrete mathematical model of tumor angiogenesis and contains two parent vessels. Blood flow through
the microvascular network and interstitial fluid flow in tumor tissues are performed by the extended Poiseuille’s law and
Darcy’s law, respectively, transvascular flow is described by Starling’s law; effects of the vascular permeability and the
interstitial hydraulic conductivity are also considered. The simulation results predict the heterogeneous blood supply, interstitial
hypertension and low convection on the inside of the tumor, which are consistent with physiological observed facts. These
results may provide beneficial information for anti-angiogenesis treatment of tumor and further clinical research.
The project supported by the National Natural Science Foundation of China (10372026). 相似文献
13.
The effect of the scheme of fluid injection into a stratum on the length and the hydraulic drag of the initial portion of
the flow through the porous medium and on the flow rate intercepted by a drainage slit separating the stratum from and end
wall is investigated. The asymptotics of large and small values of the hydraulic conductivity coefficient of this slit are
constructed.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 60–67, January–February,
1999.
The work was carried out at the Moscow State Chemical Industry Academy. 相似文献
14.
A. V. Proskurin A. M. Sagalakov 《Journal of Applied Mechanics and Technical Physics》2008,49(3):383-390
The stability of the plane flow of an electrically conducting fluid with respect to small perturbations was studied at large
Reynolds numbers in the presence of a longitudinal magnetic field. The dependence of the critical Reynolds number on the electrical
conductivity is investigated. At large Reynolds numbers, a new branch of instability and a sudden change in the critical Reynolds
numbers is found.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 3, pp. 45–53, May–June, 2008. 相似文献
15.
We benchmark a family of hybrid finite element–node-centered finite volume discretization methods (FEFV) for single- and two-phase
flow/transport through porous media with discrete fracture representations. Special emphasis is placed on a new method we
call DFEFVM in which the mesh is split along fracture–matrix interfaces so that discontinuities in concentration or saturation
can evolve rather than being suppressed by nodal averaging of these variables. The main objective is to illustrate differences
among three discretization schemes suitable for discrete fracture modeling: (a) FEFVM with volumetric finite elements for
both fractures and porous rock matrix, (b) FEFVM with lower dimensional finite elements for fractures and volumetric finite
elements for the matrix, and (c) DFEFVM with a mesh that is split along material discontinuities. Fracture discontinuities
strongly influence single- and multi-phase fluid flow. Continuum methods, when used to model transport across such interfaces,
smear out concentration/saturation. We show that the new DFEFVM addresses this problem producing significantly more accurate
results. Sealed and open single fractures as well as a realistic fracture geometry are used to conduct tracer and water-flooding
numerical experiments. The benchmarking results also reveal the limitations/mesh refinement requirements of FE node-centered
FV hybrid methods. We show that the DFEFVM method produces more accurate results even for much coarser meshes. 相似文献
16.
Norhayani Othman Bashar Jazrawi Parisa Mehrkhodavandi Savvas G. Hatzikiriakos 《Rheologica Acta》2012,51(4):357-369
The wall slip and melt fracture behaviour of several commercial polylactides (PLAs) as well as their rheological properties
under shear and extensional have been investigated. The PLAs have had weight-average molecular weights in the range of 104–105 g/mol and studied in the temperature range of 160–200°C. The solution properties and linear viscoelastic behaviour of melts
indicate linear microstructure behaviour. PLAs with molecular weights greater than a certain value were found to slip, with
the slip velocity to increase with decrease of molecular weight. The capillary data were found to agree well with linear viscoelastic
envelope once correction for slip effects was applied. The onset of melt fracture for the high molecular weight PLAs was found
to occur at about 0.2 to 0.3 MPa, depending on the geometrical characteristics of the dies and independent of temperature.
Addition of 0.5 wt.% of a polycaprolactone (PCL) into the PLA that exhibits melt fracture was found to be effective in eliminating
and delaying the onset of melt fracture to higher shear rates. This is due to significant interfacial slip that occurs in
the presence of PCL. 相似文献
17.
João Eduardo Borges Nuno H. C. Pereira Jorge Matos Kathleen H. Frizell 《Experiments in fluids》2010,48(1):17-31
The development of a three-hole pressure probe with back-flushing combined with a conductivity probe, used for measuring simultaneously
the magnitude and direction of the velocity vector in complex air–water flows, is described in this paper. The air–water flows
envisaged in the current work are typically those occurring around the rotors of impulse hydraulic turbines (like the Pelton
and Cross-Flow turbines), where the flow direction is not known prior to the data acquisition. The calibration of both the
conductivity and three-hole pressure components of the combined probe in a rig built for the purpose, where the probe was
placed in a position similar to that adopted for the flow measurements, will be reported. After concluding the calibration
procedure, the probe was utilized in the outside region of a Cross-Flow turbine rotor. The experimental results obtained in
the present study illustrate the satisfactory performance of the combined probe, and are encouraging toward its use for characterizing
the velocity field of other complex air–water flows. 相似文献
18.
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
19.
S. E. Alexandrov E. A. Lyamina 《Journal of Applied Mechanics and Technical Physics》2006,47(5):757-761
It is shown that the use of a fracture criterion containing a characteristic length of the flow region makes it possible to
further develop the theory of fracture in the vicinity of the maximum friction surfaces in metal-forming processes, with allowance
for an infinite equivalent strain rate arising near such surfaces. A model of perfectly plastic rigid solids is considered
in formulating the criterion. It is noted that the approach can be extended to more complicated models of plastic solids.
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Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 5, pp. 169–174, September–October, 2006. 相似文献
20.
Over the past few decades, significant progress of assessing chemical transport in fractured rocks has been made in laboratory
and field investigations as well as in mathematic modeling. In most of these studies, however, matrix diffusion on fracture–matrix
surfaces is considered as a process of molecular diffusion only. Mathematical modeling based on this traditional concept often
had problems in explaining or predicting tracer transport in fractured rock. In this article, we propose a new conceptual
model of fracture-flow-enhanced matrix diffusion, which correlates with fracture-flow velocity. The proposed model incorporates
an additional matrix-diffusion process, induced by rapid fluid flow along fractures. According to the boundary-layer theory,
fracture-flow-enhanced matrix diffusion may dominate mass-transfer processes at fracture–matrix interfaces, where rapid flow
occurs through fractures. The new conceptual model can be easily integrated with analytical solutions, as demonstrated in
this article, and numerical models, as we foresee. The new conceptual model is preliminarily validated using laboratory experimental
results from a series of tracer breakthrough tests with different velocities in a simple fracture system. Validating of the
new model with field experiments in complicated fracture systems and numerical modeling will be explored in future research. 相似文献