WETTABILITY AND SPREADING - 2 KEY PARAMETERS IN OIL-RECOVERY WITH 3-PHASE GRAVITY DRAINAGE

The objective of this paper is to show that the porous medium wettabil ity and the spreading characteristics of the fluid system hold the key roles in three-phase gas injection, and to study to which extent thes e two parameters affect oil recovery and phase distributions. To this end gravity assisted inert gas injection experiments have been perform ed in water-wet, oil-wet and fractionally-wet porous media for spreadi ng and nonspreading conditions. The experiments are simulated and the oil and gas relative permeabilities for three-phase flow are calculate d by history matching. It is proved that the existence of wetting and spreading oil films-caused by wettability and spreading-greatly affect s the flow mechanisms and consequently the recovery kinetics and the p rocess efficiency. The results are interpreted in terms of physicochem ical parameters on the basis of pore scale mechanisms.