Jalel Azaiez

A Semi-Unsteady-State Wellbore Steam/ Water Flow Model for Prediction of Sandface Conditions in Steam Injection Wells

A numerical nonisothermal two-phase wellbore model is developed to simulate downward flow of a steam and water mixture in the wellbore. This model entails simultaneous solution of coupled mass and momentum conservation equations inside the wellbore with an energy conservation equation for the fluids within the wellbore, surrounding medium and formation. A new drift-flux model that accounts for slip between the phases inside the wellbore is employed. In addition, a 2D implicit scheme that allows for heat transfer in both the axial and radial directions in the formation is developed. Furthermore, a rigorous nonlinear temperature- and depth-dependent overall heat transfer coefficient is implemented. The model predictions are validated against real field data and other available models. The model is useful for designing well completion and accurately computing the wellbore/formation heat transfer, which is important for estimating oil recovery by using steam injection.

Double diffusion natural convection in a rectangular enclosure filled with binary fluid saturated porous media: The effect of lateral aspect ratio

Three-dimensional, double diffusion, natural convection in a rectangular enclosure filled with binary fluid saturating porous media is investigated numerically. The effect of lateral aspect ratio on the heat, mass, and momentum transfer is systematically studied. For certain range of parameters, it is interesting to find that the flow patterns may duplicate themselves as the lateral aspect ratio increases by integer factors, which is similar to longitudinal roll formation in a Rayleigh–Benard problem. For the mentioned range of parameters the change in the lateral aspect ratio has no influence on the rates of heat and mass transfer. However, for other ranges of parameters, the flow exhibits completely different patterns and the rates of heat and mass transfer are influenced drastically compared with that of cubic cavity. In general, the flow of three- and two-dimensional results are difficult to justify, especially if interest is on the flow structure.

Stability of miscible displacements of shear thinning fluids in a Hele-Shaw cell

A linear stability analysis of the viscous fingering of miscible non-Newtonian flow displacements in a rectilinear Hele-Shaw cell is presented. The shear-thinning character of the non-Newtonian fluid is described using the Carreau model which involves two rheological parameters De and n. Flows where either the displacing or displaced phase has a shear-thinning behavior are examined and compared with those of Newtonian flows. It is found that the shear-thinning character of the non-Newtonian fluid has an important effect on the flow instability. In particular, a flow where the driving fluid is shear-thinning is always more unstable than its Newtonian counterpart. For this flow, the maximum growth rate and the spectrum of unstable wave numbers are larger than in the Newtonian case which suggests that more ramified structures will develop as the finger instability grows. On the other hand, when the displaced fluid is non-Newtonian, a stronger shear-thinning rheological behavior leads in general to a less unstable flow. The mechanisms responsible for the changes in the flow instability are explained in terms of the different sources contributing to the generation of the vorticity disturbance.

Miscible Displacements in Porous Media with Time-Dependent Injection Velocities

Miscible displacements in homogeneous porous media involving time-dependent injection velocities

Transient Nonisothermal Fully Coupled Wellbore/Reservoir Model for Gas-Well Testing, Part 1: Modelling

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Centrifugal instability of semidilute non-Brownian fiber suspensions

U(t) are analyzed. The displacements consist of periodic cycles that involve alternating stages of injection and production or of injection and soaking. Results of a linear stability analysis revealed that the growth rate of disturbances follows the overall trends of the velocity

Hydrodynamic instabilities of flows involving melting in under-saturated porous media

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