Nguyen Van Diep

A numerical model for water-oil flow in naturally fractured reservoirs

This paper describes the development of a three-dimensional , two-phase model for simulating the flow of water and oil in naturally fractured reservoirs. The model is based on the dual porosity approach. Main flow in the reservoir occurs within the fractures with local exchange of fluids between the fracture system and matrix blocks. A new formula for matrix/fracture fluid exchange rate is proposed based on an extension of the equation developed by Kazemi to account the gravity effects. This formula allows to eliminate the matrix pressure in the pressure equation for fractures and makes the solution algorithm easier. Some example calculations are presented to validate the model. These include a comparison of the results of this paper with previous results , showing the gravity effects and applicability of the model for field-scale problems.

A NUMERICAL SIMULATION OF MORPHOLOGICAL PROCESSES FOR A NAVIGATION CHANNEL

The finite difference method was applied to simulate the morphological processes for a. navigation channel Mathematical equations were based on the SUTRENCH and PROFILE models proposed by L. C. van Rijn. The difficulties of treatment for bed boundary conditions were overcame flexibly by using the interpolation functions with high accuracy. The results obtained showed that the simulation is very suitable and able to be applied to practice problems.

On an one- and quasi-two dimensional linking hydraulic model for the complex river network-validation and application

This paper describes an approach to construct an oneand quasi-two dimensional hydraulic model for the complex river network, including various hydraulic structures. The model is based on the numerical solution of the Saint-Venant equations for river branches, the continuity equation for storages, the equation for junction conditions of the confluences, tributaries , the equation for hydraulic structures between rivers and storage cells. Cross sections are modeled as a combination of main and flood plain parts to simulate better the flow pattern. The calculating program has been ~eveloped, validated by test cases, proposed by European big hydraulic research laboratories and then applied to build a hydraulic model for the complicated Red-Thai Binh river network.

A NUMERICAL INVESTIGATION OF NON-ROTATIONAL, RIGID SPHERICAL PARTICLE SEDIMENTATION PROBLEM IN VISCOUS FLUID

This paper can be considered as continuous part of [1], where the generalized diffusion theory of rigid spherical particle sedimentation in viscous fluid was investigated. Here a numerical solution of non-stationary sedimentation process is obtained by using the explicit finite difference method. The btained results show that this model can be used for qualitative study of physical phenomenon of sedimentation problem.

Some initial experimental results on the conditions of free water layer formation in horizontal pipes

This paper presents an experimental facility conducted in Hanoi Institute of Mechanics to investigate multiphase How pattern in the pipes. First and foremost, it ts used to define the conditions of water layer formation in the horizontal pipe. · I· Experimental results have been . obtained in stainless steel pipes ~f three different diameters (24.6mm; 30.8mm and 40.5mm) with white spindle oil N° 10 and water. They have been shown in the form of water layer maps.

Rheological properties of emulsion of crude oil and water

In the paper the rheological properties of crude oil of White T iger oil-field (Vietnam) and its emulsion with sea-water, including measurement results and analytical approximation formulae for wide range of pressure, temperature and water concentration, are presented. As it is known, the crude oil of White Tiger oil-field is a high-paraffin and high-viscous oil. At the low temperature (T ~ 40°C) it behaves as non-Newtonian fluid of Bingham-Shvedov group. Therefore, beside the effective viscosity, the effective dynamic shear stress is also measured and approximated. The rheological properties of crude oil and emulsion of crude oil and water are also measured and approximated for the case when the mixture contains 0.1% chemical reagent ES-3363.

An algorithm for simultaneous determination of pressure and temperature distribution in oil-producing tube flow and the counter flow in gas-lift annulus

An algorithm for simultaneous determination of pressure and temperature distribution in oil-producing tube flow and the counter flow in gas-lift annulus has been proposed. The algorithm is based on a double loop iterative procedure and shooting method. The two-phase flow calculation for pressure Used in the algorithm is based on improved methods of Beggs and Brills, Orkissewski or Hagedorn and Brown. The numerical implementation for an example is presented to assure the applicability of proposed algorithm.

Generalized diffusion theory of hydrodynamical particle migration in suspensions. Part 1: The case of equal densities

The general continuum theory has been developed for two-phase flows of fluid with deformable particles, where the micro-deformation of particles and the relative motion between phases have been taken into account [1-3]. This paper is concerned with using the simplest model from developed general theory for modeling of particle migration in suspensions- one of the most important and complicated aspects of particle-liquid two-phase flows, that has been observed and studied by many authors. For this purpose it is considered the motion of Newtonian fluid-rotating rigid spherical particles two-phase continuum with specialized nonlinear constitutive equations, when the particle and fluid have equal densities. The obtained equation system has been used for studying quantitatively particle migration problem in the circular Couette flow.

Theory of two-phase flow of fluid with rigid ellipsoidal particles

SUM:MARY. In the paper [lJ the general continuum theory has been developed for twophase of fluid with deformable particles of arbitrary form, where the microdeformation of the particles and the relative motion between phases are taken into account. The extended theory of irrotational flow of fluid caused by a moving deformable body ha.s been used to obtain the general expressions for the generalized induced mass tensors. The simplest case, when the particles have a spherical form during the micro-deformation, ~as been considered in the paper [2]. This paper is devoted to the theory of two-pha.se flow of fluid with rigid ellipsoidal particles. The obtained equation systemcan be used to determine the characteristic mean velocity, -the particle rotation, the generalized diffusion fl.ux of particles, the mass densities, the volume concentration of particles, the inertia tensor and generalized induced mass tensors of particle.

Generalized diffusion theory of micromorphicly deformable particle-fluid continuum and bubble-liquid two-phase flows

In the paper [1] the basic concepts and equations were derived for the micromorphicly deformable particle-fluid two-phase flows, the constitutive equations have been constructed. The flow us fluid with deformable spherical particles, when the particle only expands radially, rotates and translates, is considered in this paper. For this case one can obtain the full motions equations system. These equation together with the constitutive equations are sufficient to determine all of unknowns, and they can be used to study the bubble- liquid two-phase flow. The problems of kinematic wave and acoustic wave propagation in the bubble-liquid two-phase flow is studied.