Transport in Porous Media 22" 359-360, 1996. 359

Letter to the Editor

Recently (in Rose (1995), Transport in Porous Media 18: 87-93) new ideas were presented about a plausible theory which has the potential of greatly facilitating the design of experimental procedures for assessing if and when viscous coupling effects are manifested during certain cases of two-phase fluid flow of immiscible fluids in 2-D anisotropic porous media. It is now realized, however, that to easily confirm this potential, one needs only to make reference to the simple schematic diagram of Figure 1. There the fact is clearly displayed that in order to make use of Equation (3.1) in the referenced paper, two thin sample slabs, A and B, will be required whose parallel end-faces are chosen to be perpendicular, respectively, to

Fx, Fy and Jx, Jy are the x,y components of the Cartesian conjugate Force and Flux vectors.

perpendicular y-axis A thin A,B

I Fx ~ - - _~sample slabs

<,o, Fx o, T I

. ...... / / i ,, H I

preferred ~ 7 . , x - a x i s transport ~ ' " ~ Jx (for\Fx=O) Jx (for Fy=O)', direction "-. ',,

L ".. , Conductivity Ellipsoid

Fig. 1.

360 LETIER TO THE EDITOR

the x and y axes of some arbitrarily selected Cartesian reference frame. It follows that by employing these two samples in laboratory work, the eight [D1... Ds] transport coefficients of Equations (3.1) can be obtained from the laboratory data simply by taking ratios of the [J/', Fj] conjugate flux and driving force vector components associated with the transport of the [a, b] fluids. What then will still be needed are the particular transport coefficients, t.t., l[/3max', -u6rlmin', ~L" max ", ~'8/1 minlj, that are shown in Equations (3.2) to be associated with the principal directions of the conductivity ellipsoid. And in an earlier paper (cf. Rose J. Petroleum Technol. (May 1982) 1142-1144), it was already shown that when measurements are made on two (say A and B) samples whose axes are separated by a known angle, the diagonalization called for by Equations (3.2) can unambiguously be achieved.

Illini Technologists International, Champaign, IL 61825, U.S.A.

WALTER ROSE