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1.
Most gas wells produce some amount of liquid. The liquid is either condensate or water. At high rates, the gas is able to entrain liquid to the surface; however, as gas well depletes, the liquid drops back in a gas well (called liquid loading) creating a back pressure on the reservoir formation. Addition of surfactants to the well to remove liquid is one of the common methods used in gas wells. Liquid loading in vertical gas wells with and without surfactant application was investigated in this study. Anionic, two types of amphoteric (amphoteric I and amphoteric II), sulphonate and cationic surfactants were tested in 2-inch and 4-inch 40-feet vertical pipes. Pressure gradient and liquid holdup are measured. Visual observation with a high speed camera was used to gain insight into the direction of foam flow in intermittent flow and foam film flow under annular flow conditions.Liquid loading is initiated when the liquid film attached to the wall in annular flow starts flowing downwards. Introduction of foam causes the gas velocity at which film reversal occurs to decrease; this shift increases with increasing surfactant concentration and it is more pronounced in 2-inch pipe than in 4-inch pipe. That is, the benefit of surfactants is much more pronounced in 2-inch pipe than in 4-inch pipe. The reason for postponement of liquid loading is reduction in the liquid holdup at low gas velocities which reduces the liquid holdup in foam flow compared to air-water flow. However, at higher gas velocities, the pressure drop in 2-inch compared to 4-inch pipe increases rapidly as the surfactant concentration increases. The selection of optimum concentration of the surfactant is a balance between the reductions in the gas velocity at which liquid loading occurs compared to increase in the frictional loss as the concentration increases. We provide guidelines about the selection of the surfactant concentration.Visual observations using high speed camera show differences in the behavior under foam flow conditions. Unlike air-water flow, the liquid film attached to the wall is replaced by thick foam capturing the gas bubbles. The type of roll waves which carry the liquid in 2-inch pipe is different than what was observed in 4-inch pipe. Compared to 4-inch pipe, the roll waves in 2-inch pipe are much thicker. This partly explains the differences in 2-inch versus 4-inch pipe behavior. 相似文献
2.
The impact of a single drop on a wetted solid surface 总被引:8,自引:0,他引:8
The impact of single drops on a thin liquid film was studied to understand the mechanism of secondary atomisation of sprays
colliding on a wetted, cold, solid surface. To span a wide range of conditions various mixtures of water and glycerol were
used. The use of Weber number, Ohnesorge number and non-dimensional film thickness to describe the peculiarities of the phenomenon
allowed to carry out the experiments under appropriate similarity conditions. The impact of millimetric drops was analysed
in detail by photographic means, using both still photography to study impact morphology, and laser sheet visualisation to
investigate secondary droplet formation. Two mechanisms of splash were identified, depending essentially on the liquid viscosity
(Ohnesorge number), a parameter which appears to play an important role also in defining the splash morphology. A photographic
documentation is annexed. The characteristic times of the crown formation, the non-linear evolution of cusps (jet formation)
and the surface roughness influence are further discussed. The experimental results allow to propose an empirical correlation
for the splashing/deposition limit, for a wide range of conditions, and a comparison to available previous works is presented.
The influence of the film thickness and liquid viscosity on the splash is confirmed and quantified.
Received: 1 March 1996/Accepted: 12 November 1996 相似文献
3.
A thin liquid sheet present in the shear layer of a compressible gas jet is investigated using an Eulerian approach with mixed-fluid
treatment for the governing equations describing the gas–liquid two-phase flow system, where the gas is treated as fully compressible
and the liquid as incompressible. The effects of different topological configurations, surface tension, gas pressure and liquid
sheet thickness on the flow development of the gas–liquid two-phase flow system have been examined by direct solution of the
compressible Navier–Stokes equations using highly accurate numerical schemes. The interface dynamics are captured using volume
of fluid and continuum surface force models. The simulations show that the dispersion of the liquid sheet is dominated by
vortical structures formed at the jet shear layer due to the Kelvin–Helmholtz instability. The axisymmetric case is less vortical
than its planar counterpart that exhibits formation of larger vortical structures and larger liquid dispersion. It has been
identified that the vorticity development and the liquid dispersion in a planar configuration are increased at the absence
of surface tension, which when present, tends to oppose the development of the Kelvin–Helmholtz instability. An opposite trend
was observed for an axisymmetric configuration where surface tension tends to promote the development of vorticity. An increase
in vorticity development and liquid dispersion was observed for increased liquid sheet thickness, while a decreasing trend
was observed for higher gas pressure. Therefore surface tension, liquid sheet thickness and gas pressure factors all affect
the flow vorticity which consequently affects the dispersion of the liquid.
相似文献
4.
储层含水条件下致密砂岩/页岩无机质纳米孔隙气相渗透率模型 总被引:1,自引:0,他引:1
页岩及致密砂岩储层富含纳米级孔隙,且储层条件下页岩孔隙(尤其无机质孔隙)及致密砂岩孔隙普遍含水,因此含水条件下纳米孔隙气体的流动能力的评价对这两类气藏的产能分析及生产预测具有重要意义.本文首先基于纳米孔隙内液态水及汽态水热力学平衡理论,量化了储层孔隙含水饱和度分布特征;进一步在纳米孔隙单相气体传质理论的基础上,考虑了孔隙含水饱和度对气体流动的影响;最终建立了含水饱和度与气相渗透率的关系曲线. 基于本文岩心孔隙分布特征,计算结果表明:储层含水饱和度对气体流动能力的影响不容忽视,在储层含水饱和度20%的情况下,气相流动能力与干燥情况相比将降低约10%;在含水饱和度40% 的情况下,气相流动能力将降低约20%. 相似文献
5.
V. I. Terekhov V. P. Lebedev N. E. Shishkin 《Journal of Applied Mechanics and Technical Physics》2000,41(4):692-698
Results of a thcoretical and experimental study of dynamics and mass transfer during desorption of a gas from a liquid film
in the presence of a cocurrent air flow are presented. The calculation model is based on solving integral momentum and diffusion
relations for the gaseous and liquid phascs. Both laminar and turbulent regimes of the film flow are analyzed. The experimental
study of mass transfer was conducted for carbon dioxide desorption from a water film. Criterial relations for mass transfer
in the gaseous and liquid phases are obtained. The experiments showed that the heat-transfer coefficients for the case under
study are one order of magnitude grcater than those for the flow of a smooth film. Possible mechanisms of such an appreciable
intensification of the liquid-film mass transfer in a cocurrent gas flow are discussed.
Kutateladze Institute of Thermal Physics, Siberian Division, Russian Academy of Sciences, Novosibirsk 630090. Translated from
Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 41, No. 4, pp. 131–138, July–August, 2000. 相似文献
6.
针对二维微柱阵列壁面上含不溶性活性剂液滴的铺展过程,采用润滑理论建立了液膜厚度和浓度演化模型,采用数值计算方法得到了液滴的铺展特征及相关参数的影响. 研究表明:活性剂液滴在微柱阵列壁面上铺展时,在壁面凸起处衍生出隆起结构,壁面凹槽处衍生出凹陷结构,随时间持续,隆起和凹陷均向两侧移动,且数量不断增加. 活性剂液膜流经凸起时,隆起高度呈驼峰形变化. 增大预置液膜厚度或活性剂初始浓度,铺展区域隆起和凹陷数量增多,液滴铺展速度加快. 增加凹槽深度或减小斜度会使毛细力作用增强,液膜破断可能性加大;增大凹槽宽度可加速活性剂液滴的铺展,加剧液膜表面波动幅度. 相似文献
7.
Chun-Lang Yeh 《Heat and Mass Transfer》2008,44(3):275-280
The performances of three linear eddy viscosity models (LEVM) and one algebraic Reynolds stress model (ARSM) for the simulation
of turbulent flow inside and outside pressure-swirl atomizer are evaluated by comparing the interface position with available
experimental data and by comparing the turbulence intensity profiles at the atomizer exit. It is found that the turbulence
models investigated exhibit zonal behaviors, i.e. none of the models investigated performs well throughout the entire flow
field. The turbulence intensity has a significant influence on the global characteristics of the flow field. The turbulence
models with better predictions of the turbulence intensity, such as Gatski-Speziale’s ARSM model, can yield better predictions
of the global characteristics of the flow field, e.g. the reattachment lengths for the backward-facing step flow and the sudden
expansion pipe flow, or the discharge coefficient, film thickness and the liquid sheet outer surface position for the atomizer
flows. The standard k–ε model predicts stronger turbulence intensity as compared to the other models and therefore yields smaller film thickness
and larger liquid sheet outer surface position. In average, the ARSM model gives both quantitatively and qualitatively better
results as compared to the standard k–ε model and the low Reynolds number models. 相似文献
8.
The hydrodynamic instability of a film flow of a weak solution containing a soluble volatile surfactant is investigated. Diffusion
of the surfactant in the liquid, its evaporation into the boundary gas medium, and the adsorption and desorption processes
in the near-surface layer are taken into account. A system of evolutionary equations is derived and a steady-state solution
film flow along a vertical surface and the stability of this flow are investigated for the simultaneous action of body and
capillary forces and the Marangoni effect. Hydrodynamic and diffusion instability modes are detected and their properties
are investigated for constant and variable surfactant concentration in the adsorbed sublayer.
Moscow, Madrid. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 56–67, July–August,
2000.
The work was carried out with support from the Russian Foundation for Basic Research (project No. 97-01-00153) and the Spanish
Ministry of Higher Education (program DGICYT (Spain), project No. PB 96-599). 相似文献
9.
An experimental study has been performed to improve the understanding of the initial air–liquid interaction in the near field
of an air-blasted breaking water sheet. For the first time, planar laser-induced fluorescence (PLIF) has been used to visualize
the air-flow field, seeding the air streams with acetone vapor. Mie scattering from the liquid sheet, together with the acetone
fluorescence signal has enabled simultaneous determination of the instantaneous water sheet location and the air-flow structures.
The two-phase flow visualization has revealed detachment of the air boundary layer over the air–water interface behind the
zones of strong curvature. The pressure field induced by these vortices has been identified as a cause of the enhanced sheet
flapping and the instability growth.
Received: 30 October 2000/Accepted: 29 March 2001 相似文献
10.
针对二维微柱阵列壁面上含不溶性活性剂液滴的铺展过程,采用润滑理论建立了液膜厚度和浓度演化模型,采用数值计算方法得到了液滴的铺展特征及相关参数的影响. 研究表明:活性剂液滴在微柱阵列壁面上铺展时,在壁面凸起处衍生出隆起结构,壁面凹槽处衍生出凹陷结构,随时间持续,隆起和凹陷均向两侧移动,且数量不断增加. 活性剂液膜流经凸起时,隆起高度呈驼峰形变化. 增大预置液膜厚度或活性剂初始浓度,铺展区域隆起和凹陷数量增多,液滴铺展速度加快. 增加凹槽深度或减小斜度会使毛细力作用增强,液膜破断可能性加大;增大凹槽宽度可加速活性剂液滴的铺展,加剧液膜表面波动幅度. 相似文献
11.
Stone’s model for gravity segregation in gas improved oil recovery (IOR) indicates the distance that injected gas and water
travel together before the segregation being completed (length of complete segregation). This model is very useful for co-injection
of water and gas into horizontal depleted reservoirs. A proof by Rossen and van Duijn showed that Stone’s model applies to
steady-state gas–liquid flow, and also foam flow, in horizontal reservoirs as long as the standard assumptions of fractional
flow theory (incompressible flow, Newtonian mobilities, local equilibrium) are applied. However, until now, there has been
no analytical study on the length of segregation when co-injection of water and gas occurs in tilted reservoirs. In this article,
in order to extent the validity of Stone’s model to tilted reservoirs, governing equations of fluids displacement based on
fractional flow theory are solved by the method of characteristics, MOC. The results are then compared to Stone’s model and
to the results of a three-dimensional finite-difference compositional reservoir simulator. This study shows that Stone’s model
should be corrected for tilted reservoirs and that the presented math proof can model gravity segregation in gas IOR of tilted
reservoirs, appropriately. The effect of co-injecting of water and gas into tilted reservoirs on recovery efficiency is also
examined. 相似文献
12.
Slug flow is one of the representative flow regimes of two-phase flow in micro tubes. It is well known that the thin liquid film formed between the tube wall and the vapor bubble plays an important role in micro tube heat transfer. In the present study, experiments are carried out to clarify the effects of parameters that affect the formation of the thin liquid film in micro tube two-phase flow. Laser focus displacement meter is used to measure the thickness of the thin liquid film. Air, ethanol, water and FC-40 are used as working fluids. Circular tubes with five different diameters, D = 0.3, 0.5, 0.7, 1.0 and 1.3 mm, are used. It is confirmed that the liquid film thickness is determined only by capillary number and the effect of inertia force is negligible at small capillary numbers. However, the effect of inertia force cannot be neglected as capillary number increases. At relatively high capillary numbers, liquid film thickness takes a minimum value against Reynolds number. The effects of bubble length, liquid slug length and gravity on the liquid film thickness are also investigated. Experimental correlation for the initial liquid film thickness based on capillary number, Reynolds number and Weber number is proposed. 相似文献
13.
Subrata Borgohain Gogoi 《Transport in Porous Media》2011,90(2):589-604
Surfactant loss due to adsorption on the porous medium of an oil reservoir is a major concern in enhanced oil recovery. Surfactant
loss due to adsorption on the reservoir rock weakens the effectiveness of the injected surfactant in reducing oil–water interfacial
tension (IFT) and making the process uneconomical. In this study, surfactant concentrations in the effluent of the corefloods
and oil–water IFT were determined under different injection strategies. It was found that in an extended waterflood following
a surfactant slug injection, surfactant desorbed in the water phase. This desorbed surfactant lasted for a long period of
the waterflood. The concentration of the desorbed surfactant in the extended waterflood was very low but still an ultralow
IFT was obtained by using a suitable alkali. Coreflood results show an additional recovery of 13.3% of the initial oil in
place was obtained by the desorbed surfactant and alkali. Results indicate that by utilizing the desorbed surfactant during
the extended waterflood operation the efficiency and economics of the surfactant flood can be improved significantly. 相似文献
14.
O. V. Voinov 《Journal of Applied Mechanics and Technical Physics》2007,48(3):385-392
The motion of thin films of a viscous incompressible liquid in a gas under the action of capillary forces is studied. The
surface tension depends on the surfactant concentration, and the liquid is nonvolatile. The motion is described by the well-known
model of quasi-steady-state viscous film flow. The linear-wave solutions are compared with the solution using the Navier-Stokes
equations. Situations are studied where a solution close to the inviscid two-dimensional solutions exists and in the case
of long wavelength, the occurrence of sound waves in the film due to the Gibbs surface elasticity is possible. The behavior
of the exact solutions near the region of applicability of asymptotic equations is studied, and nonmonotonic dependences of
the wave characteristics on wavenumber are obtained.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 48, No. 3, pp. 103–111, May–June, 2007. 相似文献
15.
H. Louahlia-Gualous L. El. Omari P. K. Panday E Artioukhine 《Heat and Mass Transfer》2005,41(12):1066-1076
This paper presents the experimental results of the local heat transfer for falling film evaporation of water sheet by solving the inverse heat conduction problem. It is shown that the local heat transfer coefficients increase by increasing the air flow velocity, the film liquid flow rate or decreasing the inlet bulk film temperature. Correlations for the mean heat transfer coefficients in the absence of superimposed flow for the stagnation region, the thermally developed region and the bottom of the heated cylinder are proposed. 相似文献
16.
An experimental study was conducted to identify the effect of viscosity on the characteristics of liquid sheets formed by
a splash plate nozzle. Various mixtures of corn syrup and water are used to obtain viscosities in the range 1–170 mPa.s. Four
different splash plates with nozzle diameters of 0.5, 0.75, 1, and 2 mm, with a constant plate angle of 55° were tested. Liquid
sheets formed under various operating conditions were directly visualized. The sheet atomization process for the range of
parameters studied here is governed by two different mechanisms: Rayleigh–Plateau (R–P) and Rayleigh–Taylor (R–T) instabilities.
R–P occurs at the rim and R–T occurs on the thin sheet. The rim instability can be laminar or turbulent, depending on the
jet Reynolds number. The R–T instability of the sheet is observed at the outer edges of the radially spreading sheet, where
the sheet is the thinnest. It can also occur inside the sheet, due to formation of holes and ruptures. 相似文献
17.
《ournal of non Newtonian Fluid Mechanics》2002,105(1):53-78
A mathematical model is presented for surfactant-driven thin weakly viscoelastic film flows on a flat, impermeable plane. The Oldroyd-B constitutive relation is used to model the viscoelastic fluid. Lubrication theory and a perturbation expansion in powers of the Weissenberg number (We) are employed, which give rise to non-linear coupled evolution equations governing the transport of insoluble surfactant and thin liquid film thickness. Spreading on a Newtonian film is recovered to leading order and corrections to viscoelasticity are obtained at order We. These equations are solved numerically over a wide range of viscosity ratio (ratio of solvent viscosity to the sum of solvent and polymeric viscosities), pre-existing surfactant level and Peclet number (Pe). The effect of viscoelasticity on surfactant transport and fluid flow is investigated and the mechanisms underlying this effect are explored. Shear stress, streamwise normal stress and the temporal rate of change of extra shear stress generated from gradients in surfactant concentration dominate thin viscoelastic film flows whereas only shear stresses play a role in Newtonian thin film flows. Our results also reveal that, for weak viscoelasticity, the influence of viscosity ratio on the evolution of surfactant concentration and film thickness can be significant and varies considerably, depending on the concentration of pre-existing surfactant and surfactant surface diffusivity. 相似文献
18.
19.
Numerical simulation of air–water slug flows accelerated from steady states with different initial velocities in a micro tube is conducted. It is shown that the liquid film formed between the gas bubble and the wall in an accelerated flow is significantly thinner than that in a steady flow at the same instantaneous capillary number. Specifically, the liquid film thickness is kept almost unchanged just after the onset of acceleration, and then gradually increases and eventually converges to that of an accelerated flow from zero initial velocity. Due to the flow acceleration, the Stokes layer is generated from the wall, and the instant velocity profile can be given by superposition of the Stokes layer and the initial parabolic velocity profile of a steady flow. It is found that the velocity profile inside a liquid slug away from the bubble can be well predicted by the analytical solution of a single-phase flow with acceleration. The change of the velocity profile in an accelerated flow changes the balance between the inertia, surface tension and viscous forces around the meniscus region, and thus the resultant liquid film thickness. By introducing the displacement thickness, the existing correlation for liquid film thickness in a steady flow (Han and Shikazono, 2009) is extended so that it can be applied to a flow with acceleration from an arbitrary initial velocity. It is demonstrated that the proposed correlation can predict liquid film thickness at Re < 4600 within the range of ±10% accuracy. 相似文献
20.
When a solid sphere exits water at a given velocity, the liquid column is pulled out of a liquid reservoir. The present study focuses on the dynamic deformation of the liquid column and on the identification of the liquid column regime on the Weber number and dimensionless time (We-t*) map. The three-dimensional model of water exit has been established on the basis of the lattice Boltzmann method. A mass tracking algorithm was incorporated to capture the free surface, where the liquid–gas two-phase flow is simplified to a single-phase free surface flow. The surface tension is included by adding a perturbation term and the gravity as a body force is introduced in form of calculating the equilibrium distribution with an altered velocity. The contact angle condition in numerical simulation is not considered. The accuracy of the numerical results is demonstrated through the comparisons with the prior numerical and the experimental results in the literature. A parametric study has been conducted numerically on the radius and volume and of liquid column. Besides, the relationship between the pinch-off time of a liquid column and the Froude number has been obtained. Moreover, the evolution of the liquid column shape with a wide range of the Weber number and time scales are discussed based on the number of ligaments and droplets. The liquid column exhibits different characteristics and has been divided into three regimes. The transition between different regimes has been analyzed and the critical Weber number is given. 相似文献