A Study of Immiscible Fingering in Linear Models

Abstract

Recent improvements in processes for recovering viscous reserves has renewed interest in the phenomenon of immiscible fingering. This paper describes studies of immiscible fingering in linear Hele-Shaw and bead-packed models. Immiscible fingers were readily initiated in all models. The fingers, however, were damped out before traveling very far in the uniform bead packs that contained connate water. The damping mechanism is believed due to the movement of the two phases in a direction transverse to the direction of gross flow. To study the transverse flow phenomenon under controlled conditions, oil and water were injected simultaneously and side by side in linear models. Transition zones were formed that grew broader as the distance from the inlet increased. The saturation distribution in the transition zones could be described mathematically by an "immiscible dispersion coefficient" and the well known error function solution of the dispersion equation. The immiscible dispersion coefficients were found to be proportional to the interstitial velocity and proportional to the product of the bead diameter and packing inhomogeneity factor.