Surface Modification of Functionalized Multi-walled Carbon Nanotubes for EOR Using Low Salinity Seawater

Recently, nanoparticles of various types have been used in enhanced oil recovery (EOR) research studies. Their tiny size and unique structure made them potential additives to take part in fluid/fluid and fluid/rock interactions leading to increased recovery from depleted oil reservoirs. Among different nanoparticles, multi-walled carbon nanotubes, because of their functionalization and possibility of surface modification, an abundance of carbon sources and reasonable price have gained increased attention. In this work, a novel nano-complex has been synthesized by surface modification of functionalized multi-walled carbon nanotubes using cetyltrimethylammonium bromide (CTAB) surfactant and polyethylene glycol (PEG) polymer. The prepared nano-complex was then used as an EOR agent in a crude oil-low salinity seawater-dolomite system. The experimental results revealed profound reduction of IFT in the presence of the nano-complex where an IFT value of 0.5 mN/m at critical micelle concentration (CMC) of 60 ppm was recorded. Moreover, profound wettability alteration from oil-wet toward water-wet state and low adsorption of the nano-complex on dolomite surface further confirmed its applicability in EOR practices.