Numerical investigation of micellar-polymer displacement of oil from layered strata

A mathematical model developed earlier [8] is used to make a numerical investigation of the mechanism and wave dynamics of a process in layered strata consisting of hydrodynamically connected layers with different flow parameters. A study is made of a micellar solution with an exterior hydrocarbon phase, i.e., a solution that on contact with the stratal fluids forms a two-phase structure: a hydrocarbon fluid (micellar solution and stratal oil) and water with polymer admixture. The concentration of salts in the stratum is assumed to be constant.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 87–93, March–April, 1984.     

Numerical simulation of the displacement of oil by water

If the mobility of a displacing fluid is greater than the mobility of the displaced fluid, the displacement is unstable (see, for example, [1–3]), and the originally plane displacement front is broken up into irregular tongues. It follows from the linear analysis of stability that initially the amplitude of the perturbation increases exponentially, and according to [1] the extended tongues that are formed move with constant velocity relative to the displaced fluid. The intermediate stages in the development of the instability, like questions relating to a more precise formulation of the problem (which involves giving up the piston displacement approximation) remain unstudied. A natural approach to their study is through numerical simulation, which was realized for the first time in [4, 5]. Some of the results of such an investigation are presented in the present paper. In contrast to [4], the main attention is devoted to the development of regular perturbations. It is shown that for the investigated mobility ratios the development of the perturbations follows the linear theory unexpectedly long, and then arrives at a stationary asymptotic regime. We also investigate the influence of the loss of displacement stability on waterless oil extraction in the case of displacement in homogeneous and inhomogeneous strata.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 58–63, September–October, 1979.We thank L. A. Chudov for advice and discussions.     

Numerical modeling of the process of oil displacement from reservoirs with zonal nonuniformity

In extracting oil from nonuniform reservoirs a considerable fraction remains unrecovered from the zones of lesser permeability. The mechanism of displacement of oil from reservoirs with zonal nonuniformity is investigated within the framework of the two-dimensional Muskat-Meres model of combined oil, water and gas flow [1]. A wholly conservative difference scheme implicit in the saturations and pressure is used for the calculations. Various reservoir exploitation regimes are considered with the object of seeking means of improving the characteristics of the process.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 177–180, September–October, 1987.     

Numerical investigation of condensing steam flow in boundary layers

The paper describes a numerical method for the prediction of condensing steam flow within compressible boundary layers. The method is based on a simple stream function technique, which enables straightforward integration of the nucleation and droplet growth equations in a Lagrangian frame of reference. Calculations show how viscous dissipation and reduced expansion rate within a typical boundary layer influence nucleation and growth, leading to droplet radii and size distributions that differ substantially from those predicted in inviscid flow. The impact of condensation on temperature and velocity profiles, and the implications for thermodynamic loss are also considered.     

Nonisothermal displacement of oil by water from thermally noninsulated strata

A study is made of one-dimensional nonisothermal processes of oil displacement by water in the presence of heat transfer between the stratum and the surrounding rocks. The simplest (Newtonian) heat transfer scheme is assumed: The temperature T₀ of the surrounding rocks is assumed to be constant, and the heat flux through the bottom and top of the stratum to be proportional to the difference between the local temperature T of the stratum and T₀. This heat transfer scheme corresponds well to the conditions of laboratory simulation. The stratum is assumed to be thin, and the treatment is limited to the case of the large-scale approximation [1], for which the main mechanism of heat transport in the stratum is convective transport. Solutions are constructed by the method of characteristics [2–5]. An investigation is made of displacement processes in the case of continuous injection of hot water, in the case when a slug of hot water propelled through the stratum by cold water is used, and also in the case when there is a time lag of the thermal effect [6], the initial stage of the displacement being isothermal. The displacement of oil by water whose temperature is lower than the initial temperature of the stratum is considered. The influence of heat transfer on the structure of the displacement front is analyzed. The laws of propagation of the front of the heat wave and the saturation discontinuities are found by quadrature.     

Nonisothermal displacement of oil by a solution of an active additive

In earlier work [1, 2] mathematical models have been constructed for processes of displacement of oil from a porous medium by a solution of an active additive, i.e., an additive capable of changing the hydro-dynamic characteristics of the fluid and the medium. An additive of this kind that was considered was a polymer that in the dissolved state influences the properties of the displacing fluid and in the adsorbed state the permeability of the porous medium. Self-similar solutions were obtained corresponding to the problem of frontal displacement from a homogeneous porous medium, and a number of numerical calculations were made. It is natural to generalize this treatment by introducing into the problem a second active factor, which is here taken to be the temperature of the injected fluid. The analysis of the nonisothermal displacement of oil by a solution of an active additive can be transferred without significant modifications to the general problem of displacement of oil by a solution carrying two active agents. The names additive and temperature are retained here only for convenience of exposition.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 90–107, November–December, 1980.We thank A. A. Barmin, A. G. Kulikovskii, and L. A. Chudov for helpful discussions.     

Numerical investigation of the flow front behaviour in the co‐injection moulding process

This paper presents a three‐dimensional (3D) solution algorithm for solving the sequential co‐injection moulding process. The flow of skin and core materials inside a rectangular cavity is investigated both numerically and experimentally. A 3D finite element flow analysis code is used to solve the governing equations of the non‐isothermal sequential co‐injection moulding. The predicted flow front behaviour is compared to the experimental observations for various skin/core volume ratio, injection speed, injection temperature, and core injection delay. Simulation results are in good agreement with experimental data and indicate correctly the trends in solution change when processing parameters are changing. Solutions are also shown for the filling of a spiral‐flow mould. The numerical approach is shown to predict the core expansion phase during which the flow front of core and skin materials advance together without breakthrough. Breakthrough phenomena is also predicted and the numerical solution is in good agreement with the experiment. Copyright © 2005 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.     

Theoretical analysis of microscopic oil displacement mechanism by viscoelastic polymer solution

The microscopic oil displacement mechanism in viscoelastic polymer flooding is theoretically analyzed with mechanical method. The effects of viscoelasticity of polymer solution on such three kinds of residual oil as in pore throat, in sudden expansion pore path, and in dead end are analyzed. Results show that the critical radius of mobile residual oil for viscoelastic polymer solution is larger than that for viscous polymer solution, which makes the oil that is immobile in viscous polymer flooding displaced under the condition of viscoelastic polymer solution. The viscous polymer solution hardly displaces the oil in dead ends. However, when the effect of viscoelasticity is considered, the residual oil in sudden expansion pore paths and dead ends can be partly displaced. A dimensionless parameter is suggested to denote the relative dominance of gravity and capillary pressure. The larger the dimensionless parameter, the more accurate the increment expressions.     

An investigation of two-dimensional flows of nucleating and wet steam by the time-marching method

A numerical method for the solution of two-dimensional two-phase flows of steam is described. Comparisons are with two sets of experimental results in nozzles and the agreement obtained is satisfactoryy. Some predictions of two-phase effects in blade cascades are also presented.     

Numerical investigation of the effects of turbulence on the ignition process in a turbulent MILD flame

Acta Mechanica Sinica - In this study, we conduct three-dimensional nonlinear large-eddy simulation to investigate the interaction between turbulence and reaction during the initial ignition...