Effect of Wettability Alteration on Water/Oil Relative Permeability, Dispersion, and Flowable Saturation in Porous Media

Summary Wettability alteration was shown to affect strongly water/oil two-phase flow behavior in Berea and Loudon reservoir cores. Two examples of wettability alteration were realized by core aging and core extraction. With a steady-state method coupled with tracer analyses, these changes in wettability were shown to affect relative permeabilities, dispersivities, and flowable saturations in the cores. The changes in wettability were also confirmed by waterfloods and spontaneous-imbibition tests. Dispersion in steady-state two-phase flow was found to be a strong function of saturation and wettability. Dispersivity of each phase increases with decreasing phase saturation. Flow of the non wetting phase was dispersed much more than that of the wetting phase. A large fraction of the nonwetting-phase saturation was found to be bypassed or nonflowable, while the wetting phase was completely flowable. The correlation between the flowable phase saturation and in-situ phase saturation was strongly affected by wettability alteration.