Enhanced Oil Recovery Using Oleic Acid-Modified Titania Nanofluids: Underlying Mechanisms and Oil-Displacement Performance

Abstract

Oleic acid-modified titania (OA-TiO2) nanoparticles are synthesized for the application of enhanced oil recovery (EOR) in low-permeability reservoirs. The oleic acid is grafted onto the surface of titania by the esterification reaction under a specific condition. The well-dispersed OA-TiO2 is expected to exhibit an excellent interfacial activity and a strong wettability alteration capability, owing to its amphiphilic features. This work aims to explore the potential of employing OA-TiO2 in EOR and to unveil its mechanisms of displacing oil in porous media. The interfacial properties of OA-TiO2 are systematically investigated by determining its interfacial tension and contact angle. A microfluidic test on a 2.5-D microfluidic model and a series of core floods are carried out to study the oil-displacement efficiency of OA-TiO2 nanofluids. The experimental results demonstrate that oleic acid-modified titania nanoparticles show great potential in not only reducing the injection pressure but also enhancing hydrocarbon recovery in low-permeability reservoirs.