Polymer-Coated Silica Nanoparticles for Enhanced Oil Recovery in Water-Wet Berea Sandstone Core Plugs

Innovative enhanced oil recovery (EOR) technologies are needed to ensure a more economical oil production to meet the growing energy demand. Silica nanoparticles have been widely studied for EOR applications due to their unique physical and chemical properties. Recent studies have proposed a renewed application of polymer-coated silica nanoparticles (PSiNPs) to overcome stability issues induced by ionic strength in injection water; however, their effect on the EOR process has not been fully addressed. In this work, we evaluated four types of PSiNPs as additives to injection water for EOR in water-wet rocks through measurements of interfacial tension (IFT), wettability index and core flood experiments. The experimental results showed that PSiNPs, at 0.1 wt%, can increase oil recovery up to 15% point compared with 40% of original oil in place (OOIP) from water flood, in secondary mode. In tertiary EOR mode, the incremental oil recovery is varied from 4.6 to 10% of OOIP. Moreover, the PSiNPs altered the wettability of the rock surface to a more water-wet condition, decreased the IFT between oil and water, and increased the injection pressure.