Janus Nanoparticles for Enhanced Oil Recovery EOR: Reduction of Interfacial Tension

Abstract

Abstract Today, global energy demand increases significantly, but supply growth does not increase in the same proportion. The oil industry has been affected by the shortage of discoveries of new deposits of oil. Thus, it is compelling the development of cost-effective enhanced oil recovery (EOR) alternatives that allow the increase of the current hydrocarbons supply of actual reservoirs. Hence, the nanotechnology emerges as a good option as the use of nanoparticles and nanofluids has shown potential benefits in improving the efficiency of chemical treatments. Nevertheless, field applications of nanoparticles have been avoided due to current studies indicate that nanoparticles concentrations higher than 10,000 mg/L are needed, which disable the implementation due to high costs and the possibility of formation damage. Hence, the main objective of this study is the development for the first time of unconventional and engineered designed 0-D nanomaterials, namely NiO/SiO2 Janus nanoparticles that can be used for enhancing the oil recovery at low concentrations (~100 mg/L) without the risk of formation damage in the reservoir. These type of nanoparticles, due to its low size and 0-D characteristics, can improve the swept efficiency in the reservoir and increase the recovery. The primary mechanism of these nanomaterials is their strategic positioning at the oil/water interface and reduction of the interfacial tension. The Janus nanoparticles can migrate at the oil/water interface. The Janus-based nanofluids (nanomaterials dispersed in determined carrier fluid) flooding were assessed for reducing the interfacial tension (IFT), increasing the viscosity of the displacement phase, and altering the rock wettability, which impacts the capillary number and hence increases the crude oil recovery. The synthesized nanomaterials were characterized by TEM, stability, IFT, rheology, contact angle measurements and coreflooding tests under real reservoir conditions (fluids, pressure, temperature and rock samples) looking for flow assurance previous to a field trial. The results showed an increase of the capillary number at a very low concentration of 100 mg/L of both nanomaterials, mainly attributed to the decrease in the interfacial tension, which can lead to the increase of the oil recovery. Displacement tests using conventional SiO2 nanoparticles-based nanofluid at a concentration of 100 mg/L did not show an increase in oil recovery regarding the one obtained in the waterflooding step. Meanwhile, the nanofluid based on the engineering designed nanomaterials at the same concentration of 100 mg/L showed an increase in oil recovery up to 50%.