STEADY-STATE 2-PHASE FLOW-THROUGH PLANAR AND NONPLANAR MODEL POROUS-MEDIA

A comparative experimental study of 'steady-state' two-phase flow in t wo types of model porous media is made to determine the effects of non planarity on the flow mechanisms and the mesoscopic flow behavior. The two model porous media have virtually the same pore geometry, but one has a planar network skeleton, whereas the other has a nonplanar (two -layer) skeleton. The latter is a new type of model porous medium that permits detailed visual observation and quantitative measurements wit hout sacrificing the 3D character of the pore network topology. The ca pillary number and the flowrate ratio are changed systematically, wher eas the viscosity ratio and the wettability (contact angle) are kept c onstant. Conventional relative permeabilities are determined and corre lated with the porescale flow phenomena. In the range of parameter val ues investigated, the flow mechanism observed was ganglion dynamics (i ntrinsically unsteady, but giving a time-averaged steady-state). The n onplanarity is shown to have small qualitative but significant quantit ative effects. In the nonplanar porous medium, the ganglion size distr ibution is wider, the mean ganglion size larger, and the stranded gang lia are fewer than those in the planar one, under the same flow condit ions.