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1.
侯健 《应用数学和力学(英文版)》2004,25(6):694-702
IntroductionMisciblefloodingisadriveprocessbymixinginjectionfluid (solvent)andoil.Itsmainmechanismistodecreasetheresidualoilsaturationbyeliminatinginterfacialtensionbetweenphases.GasdrivehasanincreasingpercentageofEORprojectsinU .S .A .,Canadaandsomeothercountriesyearsbyyears.From 1960’s ,carbondioxideinjectionhasbeingstudiedinDaqingoilfieldofChina ,buttheprocessisslowforlackinggasresource .Inrecentyears,withtheinconsistentinreserve_productionequilibriumbecomingmoreseriousandthediscoveryo… 相似文献
2.
HOUJian 《应用数学和力学(英文版)》2004,25(6):694-702
According to the research theory of improved black oil simulator, a practical mathematical model for C02 miscible flooding was presented. In the model, the miscible process simulation was realized by adjusting oil/gas relative permeability and effective viscosity under the condition of miscible flow. In order to predict the production performance fast, streamline method is employed to solve this model as an alternative to traditional finite difference methods. Based on streamline distribution of steady-state flow through porous media with complex boundary confirmed with the boundary element method (BEM), an explicit total variation diminishing (TVD) method is used to solve the one-dimensional flow problem. At the same time, influences of development scheme, solvent slug size, and injection periods on CO2 drive recovery are discussed. The model has the advantages of less information need, fast calculation, and adaptation to calculate CO2 drive performance of all kinds of patterns in a random shaped porous media with assembly boundary. It can be an effective tool for early stage screening andmiscible oil field.reservoir dynamic management of the CO2 miscible oil field. 相似文献
3.
Carbon dioxide (CO2) injection is a well-established method for increasing recovery from oil reservoirs. However, poor sweep efficiency has been
reported in many CO2 injection projects due to the high mobility contrast between CO2 and oil and water. Various injection strategies including gravity stable, WAG and SWAG have been suggested and, to some extent,
applied in the field to alleviate this problem. An alternative injection strategy is carbonated water injection (CWI). In
CWI, CO2 is delivered to a much larger part of the reservoir compared to direct CO2 injection due to a much improved sweep efficiency. In CWI, CO2 is used efficiently and much less CO2 is required compared to conventional CO2 flooding, and hence the process is particularly attractive for reservoirs with limited access to large quantities of CO2 (offshore reservoirs or reservoirs far away from inexpensive natural CO2 resources). This article describes the results of a pore-scale study of the process of CWI by performing high-pressure visualisation
flow experiments. The experimental results show that CWI, compared to unadulterated (conventional) water injection, improves
oil recovery as both a secondary (before water flooding) and a tertiary (after water flooding) recovery method. The mechanisms
of oil recovery by CWI include oil swelling, coalescence of the isolated oil ganglia and flow diversion due to flow restriction
in some of the pores as a result of oil swelling and the resultant fluid redistribution. In this article the potential benefit
of a subsequent depressurisation period on oil recovery after the CWI period is also investigated. 相似文献
4.
Chemical flooding in the petroleum industry has a larger scale of oil recovery efficiency than water flooding. On the other
hand, it is far more technical, costly, and risky. Numerical reservoir simulation can be employed to conduct mechanism study,
feasibility evaluation, pilot plan optimization, and performance prediction for chemical flooding to improve recovery efficiency
and reduce operational costs. In this article, we study numerical simulation of chemical flooding such as alkaline, surfactant,
polymer, and foam (ASP+foam) flooding. The main displacement mechanisms in this type of flooding are interfacial tension lowering,
capillary desaturation, chemical synergetic effects, and mobility control. The model of chemical flooding involves such physicochemical
phenomena as dispersion, diffusion, adsorption, chemical reactions, and in situ generation of surfactant from acidic crude
oil. The numerical simulator is based on a sequential solution approach that solves both pressure and compositions implicitly,
and is applied to three experiments, a chemical flow without mass transfer between phases, a laboratory sandstone core, and
an ASP+foam displacement problem with mass transfer, and to a real oilfield. A comparison with UTCHEM is also performed. These
applications and comparison indicate that this numerical simulator is practical, efficient, and accurate for simulating complex
chemical flooding processes.
相似文献
5.
6.
Carbonated water injection (CWI) is a CO2-augmented water injection strategy that leads to increased oil recovery with added advantage of safe storage of CO2 in oil reservoirs. In CWI, CO2 is used efficiently (compared to conventional CO2 injection) and hence it is particularly attractive for reservoirs with limited access to large quantities of CO2, e.g. offshore reservoirs or reservoirs far from large sources of CO2. We present the results of a series of CWI coreflood experiments using water-wet and mixed-wet Clashach sandstone cores and
a reservoir core with light oil (n-decane), refined viscous oil and a stock-tank crude oil. The experiments were carried out to assess the performance of CWI
and to quantify the level of additional oil recovery and CO2 storage under various experimental conditions. We show that the ultimate oil recovery by CWI is higher than the conventional
water flooding in both secondary and tertiary recovery methods. Oil swelling as a result of CO2 diffusion into the oil and the subsequent oil viscosity reduction and coalescence of the isolated oil ganglia are amongst
the main mechanisms of oil recovery by CWI that were observed through the visualisation experiments in high-pressure glass
micromodels. There was also evidence of a change in the rock wettability that could also influence the oil recovery. The coreflood
test results also reveal that the CWI performance is influenced by oil viscosity, core wettability and the brine salinity.
Higher oil recovery was obtained with the mixed-wet core than the water-wet core, with light oil than with the viscous oil
and low salinity carbonated brine than high-salinity carbonated brine. At the end of the flooding period, an encouraging amount
of the injected CO2 was stored in the brine and the remaining oil in the form of stable dissolved CO2. The experimental results clearly demonstrate the potential of CWI for improving oil recovery as compared with the conventional
water flooding (secondary recovery) or as a water-based EOR (enhanced oil recovery) method for watered out reservoirs. 相似文献
7.
Dual Mesh Method for Upscaling in Waterflood Simulation 总被引:4,自引:0,他引:4
Detailed geological models typically contain many more cells than can be accommodated by reservoir simulation due to computer time and memory constraints. However, recovery predictions performed on a coarser upscaled mesh are inevitably less accurate than those performed on the initial fine mesh. Recent studies have shown how to use both coarse and fine mesh information during waterflooding simulations. In this paper, we present an extension of the dual mesh method (Verdière and Guérillot, 1996) which simulates water flooding injection using both the coarse and the original fine mesh information. The pressure field is first calculated on the coarse mesh. This information is used to estimate the pressure field within each coarse cell and then phase saturations are updated on the fine mesh. This method avoids the most time consuming step of reservoir simulation, namely solving for the pressure field on the fine grid. A conventional finite difference IMPES scheme is used considering a two phase fluid with gravity and vertical wells. Two upscaling methodologies are used and compared for averaging the coarse grid properties: geometric average and the pressure solve method. A series of test cases show that the method provides predictions similar to those of full fine grid simulations but using less computer time. 相似文献
8.
9.
Saber Mohammadi Mohsen Masihi Mohammad Hossein Ghazanfari 《Transport in Porous Media》2012,91(3):973-998
Many heavy oil reservoirs contain discontinuous shales which act as barriers or baffles to flow. However, there is a lack
of fundamental understanding about how the shale geometrical characteristics affect the reservoir performance, especially
during polymer flooding of heavy oils. In this study, a series of polymer injection processes have been performed on five-spot
glass micromodels with different shale geometrical characteristics that are initially saturated with the heavy oil. The available
geological characteristics from one of the Iranian oilfields were considered for the construction of the flow patterns by
using a controlled-laser technology. Oil recoveries as a function of pore volumes of injected fluid were determined from analysis
of continuously recorded images during the experiments. We observed a clear bypassing of displacing fluid which results in
premature breakthrough of injected fluid due to the shale streaks. Moreover, the results showed a decrease of oil recovery
when shales’ orientation, length, spacing, distance of the shale from production well, and density of shales increased. In
contrast, an increase of shale discontinuity or distance of the shale streak from the injection well increased oil recovery.
The obtained experimental data have also been used for developing and validating a numerical model where good matching performance
has been observed between our experimental observations and simulation results. Finally, the role of connate water saturation
during polymer flooding in systems containing flow barriers has been illustrated using pore level visualizations. The microscopic
observations confirmed that besides the effect of shale streaks as heterogeneity in porous medium, when connate water is present,
the trapped water demonstrates another source of disturbance and causes additional perturbations to the displacement interface
leading to more irregular fingering patterns especially behind the shale streaks and also causes a reduction of ultimate oil
recovery. This study reveals the application of glass micromodel experiments for studying the effects of barriers on oil recovery
and flow patterns during EOR processes and also may provide a set of benchmark data for recovery of oil by immiscible polymer
flood around discontinuous shales. 相似文献
10.
The concept of improving oil recovery through polymer flooding is analysed. It is shown that while the injection of a polymer solution improves reservoir conformance, this beneficial effect ceases as soon as one attempts to push the polymer solution with water. Once water injection begins, the water quickly passes through the polymer creating a path along which all future injected water flows. Thus, the volume of the polymer slug is important to the process and an efficient recovery would require that the vast majority of the reservoir be flooded by polymer. It is also shown that the concept of grading a polymer slug to match the mobilities of the fluids at the leading and trailing edges of a polymer slug does not work in a petroleum reservoir. While this process can supply some additional stability to the slug, it is shown that for the purposes of enhanced oil recovery this additional stability is not great enough to be of any practical use. It is found that in this case the instability has simply been hidden in the interior of the slug and causes the same sort of instability to occur as was the case for the uniform slug. 相似文献
11.
Chemical flooding is one of the effective technologies to increase oil recovery of petroleum reservoirs after water flooding. Above the scale of representative elementary volume (REV), phenomenological modeling and numerical simulations of chemical flooding have been reported in literatures, but the studies alike are rarely conducted at the pore-scale, at which the effects of physicochemical hydrodynamics are hardly resolved either by experimental observations or by traditional continuum-based simulations. In this paper, dissipative particle dynamics (DPD), one of mesoscopic fluid particle methods, is introduced to simulate the pore-scale flow in chemical flooding processes. The theoretical background, mathematical formulation and numerical approach of DPD are presented. The plane Poiseuille flow is used to illustrate the accuracy of the DPD simulation, and then the processes of polymer flooding through an oil-wet throat and a water-wet throat are studies, respectively. The selected parameters of those simulations are given in details. These preliminary results show the potential of this novel method for modeling the physicochemical hydrodynamics at the pore scale in the area of chemical enhanced oil recovery. 相似文献
12.
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
13.
Sensitivity Analysis of the Dimensionless Parameters in Scaling a Polymer Flooding Reservoir 总被引:1,自引:0,他引:1
A set of scaling criteria of a polymer flooding reservoir is derived from the governing equations, which involve gravity and
capillary force, compressibility of water, oil, and rock, non-Newtonian behavior of the polymer solution, absorption, dispersion,
and diffusion, etc. A numerical approach to quantify the dominance degree of each dimensionless parameter is proposed.With
this approach, the sensitivity factor of each dimensionless parameter is
evaluated. The results show that in polymer flooding, the order of the sensitivity factor ranges from 10−5 to 100 and the dominant dimensionless parameters are generally the ratio of the oil permeability under the condition of the irreducible
water saturation to water permeability under the condition of residual oil saturation, density, and viscosity ratios between
water and oil, the reduced initial oleic phase saturation and the shear rate exponent of the polymer solution. It is also
revealed that the dominant dimensionless parameters may be different from case to case. The effect of some physical variables,
such as oil viscosity, injection rate, and permeability, on the dominance degree of the dimensionless parameters is analyzed
and the dominant ones are determined for different cases. 相似文献
14.
This paper examines the two-phase flow for a horizontal well penetrating a naturally fractured reservoir with edge water injection
by means of a fixed streamline model. The mathematical model of the vertical two-dimensional flow or oil-water for a horizontal
well in a medium with double-porosity is established, and whose accurate solutions are obtained by using the characteristic
method. The saturation distributions in the fractured system and the matrix system as well as the formula of the time of water
free production are presented. All these results provide a theoretical basis and a computing method for oil displacement by
edge water from naturally fractured reservoirs. 相似文献
15.
16.
A. A. Dehghan S. A. Farzaneh R. Kharrat M. H. Ghazanfari D. Rashtchian 《Transport in Porous Media》2010,83(3):653-666
This study concerns with the microscopic and macroscopic fluid distribution and flow behavior during water alternating solvent
(WAS) injection process to heavy oil using micromodel generated from thin section of a real rock which has rarely attended
in the available literature. In this study, a one-quarter five-spot glass micromodel was deployed to examine the effect of
flow media topology on microscopic displacements as well as macroscopic efficiency of WAS process. The micromodel was initially
saturated with the heavy oil, and then the hydrocarbon solvent and water were injected alternately into it. The observations
confirmed that WAS injection scheme is an effective method for the recovery of the significant amount of residual oil. Using
solvent as the leading batch in WAS scheme can really improve the oil recovery by increasing the amount of microscopic sweep
efficiency in flow paths, where the molecular diffusion in solvent–heavy oil system occurs. Presence of connate water in WAS
scheme can improve the recovery efficiency especially at higher water saturations. Heterogeneity of the medium caused the
water to be distributed better in the medium, but the amount of residual oil in the flow area is going to be increased. Small
precipitates of asphaltene particles due to solvent injection and localized entrapment of the oil due to heterogeneity effects,
water blockage, and deadend pores were observed mainly in this process. The results of this study reveals the pore scale events
in WAS injection process and will be helpful for developing reliable simulation models. 相似文献
17.
This paper describes the numerical solution of the 1D shallow‐water equations by a finite volume scheme based on the Roe solver. In the first part, the 1D shallow‐water equations are presented. These equations model the free‐surface flows in a river. This set of equations is widely used for applications: dam‐break waves, reservoir emptying, flooding, etc. The main feature of these equations is the presence of a non‐conservative term in the momentum equation in the case of an actual river. In order to apply schemes well adapted to conservative equations, this term is split in two terms: a conservative one which is kept on the left‐hand side of the equation of momentum and the non‐conservative part is introduced as a source term on the right‐hand side. In the second section, we describe the scheme based on a Roe Solver for the homogeneous problem. Next, the numerical treatment of the source term which is the essential point of the numerical modelisation is described. The source term is split in two components: one is upwinded and the other is treated according to a centred discretization. By using this method for the discretization of the source term, one gets the right behaviour for steady flow. Finally, in the last part, the problem of validation is tackled. Most of the numerical tests have been defined for a working group about dam‐break wave simulation. A real dam‐break wave simulation will be shown. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
18.
基于三维网络模型的水驱油微观渗流机理研究 总被引:11,自引:0,他引:11
利用逾渗网络模型在微观水平进行随机模拟来研究水驱油的微观渗流规律,通过模型计
算结果与油水稳态相对渗透率驱替实验结果对比验证了网络模拟的有效性. 在此基础上,讨
论了在不同润湿条件下、水驱不同阶段的剩余油微观分布规律. 将剩余油分布形态归纳为4
种状态:孤粒/孤滴状、斑块状、网络状和油水混合状态. 研究表明,网络状剩余油的块数
较少,但所占体积比例较大. 随着剩余油饱和度的降低,最大网络状油所占孔隙数减少,剩
余油饱和度在40{\%}$\sim$50{\%}附近开始以较快速度减少. 润湿性不仅影响驱油效率,也影响剩余油分布形态. 在驱替过程中,剩余油分布总的变化趋势是逐渐趋于分散. 相似文献
19.
In a WAG process (Water Alternate Gas), water and a miscible solvent (gas) are injected into a reservoir containing water and oil. The solvent will finger through the oil, leading to early breakthrough and poor recovery. Compared with a miscible flood, when only solvent is injected, fingering is supressed by the simultaneous injection of water, since this reduces the apparent mobility contrast between the injected and displaced fluids. The fingering in a miscible flood, with only hydrocarbon flowing, can be modelled successfully using a Todd and Longstaff fractional flow. In this paper, we demonstrate how to modify the effective Todd and Longstaff mobility ratio self-consistently to account for fingering in three component systems. The resultant empirical equations of flow are solved exactly in one dimension and are in excellent agreement with the averaged saturation and concentration profiles computed using two dimensional high resolution simulation, for a variety of injected water saturations, in both secondary and tertiary displacements. 相似文献
20.
The planar contraction flow is a benchmark problem for the numerical investigation of viscoelastic flow. The mathematical model of three‐dimensional viscoelastic fluids flow is established and the numerical simulation of its planar contraction flow is conducted by using the penalty finite element method with a differential Phan‐Thien–Tanner constitutive model. The discrete elastic viscous split stress formulation in cooperating with the inconsistent streamline upwind scheme is employed to improve the computation stability. The distributions of velocity and stress obtained by simulation are compared with that of Quinzani's experimental results detected by laser–doppler velocimetry and flow‐induced birefringence technologies. It shows that the numerical results agree well with the experimental results. The numerical methods proposed in the study can be well used to predict complex flow patterns of viscoelastic fluids. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献