Regarding the most reservoirs around the world are experiencing their second half of life, the need for an appropriate EOR method utilizing efficient new technologies gets more important. Nanotechnology is an advanced technology finding its place in EOR processes as it provides a high potential for oil and gas recovery.
In this study, a special type of polysilicon nanoparticle (HLP, Hydrophobic and Lipophilic Polysilicon) is investigated as an EOR agent during different water injection scenarios. The water-wet sandstone core samples are employed. Injection of HLP nanoparticle dispersed in a carrier fluid can improve oil recovery through two mechanisms: reduction of interfacial tension and wettability alteration. Reduction of interfacial tension improves pore-scale displacement efficiency. In addition, wettability alteration towards less water-wet condition provides an ideal wetting state increasing oil recovery. Three scenarios of HLP nanofluid injections are applied. First, the nanofluid is injected after waterflooding at ultimate oil saturation. Second, 3 pore-volume water injection is applied after the sequence of water and HLP nanofluid injections. Third, HLP nanofluid is injected from beginning. HLP nanofluid application lowers the oil-water interfacial tension by a factor of ten as well as changing the contact angle from 123° to 99°indicating less water wet condition. The experienced oil recoveries and pressure drops during the experiments are reported for each scenario. In all scenarios, the most of oil recovered through the first injected pore volume. According to oil recoveries, nanofluid injection from the beginning can enhance oil production considerably in compare to the other ones. Moreover, pressure drop data indicate severe permeability impairment after three pore-volume injection of nanofluids. Experimentally, nanotechnology has proved its potential to enhance oil recovery however many aspects are still in progress to be known.