An Evaluation of Spontaneous Imbibition of Water into Oil-Wet Carbonate Reservoir Cores Using Nanofluid

Nanotechnology continues to develop rapidly in the oil industry, and the main objective of this program is to identify applications that could bring significant benefits to enhanced oil recovery. It is well known that chemical agents are able to improve the spontaneous imbibition of water into oil-wet carbonates as wettability modifiers. However, the role of nanoparticles in this field is still in its infancy, and consequently, has attracted the attention of many researchers. In this work, the oil recovery from oil-wet samples was compared using aqueous solutions of a cationic surfactant (C12TAB) and synergic blend of SiO2 Nanoparticles and surfactant (nanofluid) at room temperature (23 degrees C). We also evaluated the potential of nanoparticles to change surface wettability and oil-water interfacial tension by using the contact-angle and pendent-drop method, respectively. The results show a change toward more water-wet condition and an increase in oil-water interfacial tension after application of nanoparticles. An increase in interfacial tension, and consequently, capillary pressure, will lead to a stronger imbibition of water into small pores after wettability alteration to water-wet condition. For the imbibition experiments, about 46% of original oil in place was recovered using surfactant, while an additional 10% was the average recovery using nanofluid. Therefore, the imbibition of aqueous C12TAB solution into the core improved when nanoparticles were added to it.