A Dynamic Network Model for Imbibition

摘要

A dynamic network model for imbibition based on arnphysically realistic and mathematically rigorous treatmentrnof the complex dynamics of frontal displacements, filmrnswelling, snap-off and snap-off nucleated displacements isrndescribed. Many of the previously reported observationsrnin micro-model displacements, X-ray CT measured satu-rnration profiles in core floods and the competition betweenrnfrontal displacements and snap-off all arise as a naturalrnconsequence of the dynamics of the model.rnThe model is used to study the effect of displacement raternon imbibition patterns, relative permeabilities and residualrnsaturations. The model shows that at very low displace-rnment rates the displacement is dominated by film swellingrnand snap-off with a displacement pattern similar to bondrnpercolation. Trapping is extensive and relative permeabil-rnities are low. At high displacement rates snap-off is com-rnpletely suppressed and the displacement pattern is similarrnto invasion percolation. Trapping is low and relative per-rnmeabilities are high.