Steady-state cocurrent flow observation

TABLE II. STEADY STATE COCURRENT FLOW OBSERVATIONS... 

A novel flow cell has been developed to observe on a microscopic level the steady state, cocurrent flow of two pre-equilibrated phases in a porous medium. It consists of a rectangular capillary tube packed with a bilayer of monodisperse glass beads 109 microns in diameter. The pore sizes in the model are of the order of magnitude of those in petroleum reservoirs. An enhanced videomicroscopy and digital imaging system is used to record and analyze the flow data. 

The results of the two-phase, steady state, cocurrent flow experiments are summarized in Table II. The various fluid systems from Table I are listed along with selected injection rates and corresponding capillary numbers. Each velocity shown is the sum of the superficial velocities for the two fluids or, equivalently, the ratio of the superficial velocity of either fluid to its fractional flow. The utility of this quantity is discussed later. The viscosities given and used in calculating Ca are those of the wetting phases in the various systems. Most of the data are for 1 1 injection ratios. The observed flow mechanisms are given in the last column of Table II. 

The mechanisms of steady state, cocurrent, two-phase flow through a model porous medium have been established for the complete range of capillary numbers of interest in petroleum recovery. A fundamental understanding of the mobile ganglia behavior observed requires a knowledge of how phases break up during flow through porous media. Several mechanisms have been reported in the literature and two have been observed in this flow cell. 

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