Sharif Digital Repository

Imbibition process is known to be an important recovery mechanism in naturally fractured reservoirs with water-wet matrix blocks that are imposed to water influx from an active aquifer or water flooding. Matrix blocks which are subjected to water flooding or water invasion from active aquifers do not become immersed in water at once, but they experience gradual rising of water in fracture. But most of imbibition studies are performed under conditions of totally immersed cores in static aqueous phase. Surfactants are known to reduce residual oil saturation by decreasing interfacial tension (IFT) between oil and water. On the other hand, considerable reduction of IFT due to surfactant... 

Gravity drainage is the self-propulsion of oil downward in the reservoir rock. Under favorable natural and operational conditions, it has been found to effect recoveries comparable to water displacement. With modern technical knowledge, the operator can often make a choice between dissolved gas drive, water drive and gravity drainage as the principal recovery agent in a reservoir. So far, gravity drainage has received less consideration than the other two. Gravity drainage is one of the most important processes taking place in fractured reservoirs and it plays a major role in oil recovery from low permeability matrix blocks during gas injection process. Gravity drainage is responsible for...