The Role of Nanoparticles in Enhanced Oil Recovery (EOR)

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Enhanced oil recovery (EOR) refers to the injection of water/gas with possible additives into a petroleum reservoir to produce more oil. EOR typically targets post waterflood or gas flood residual oil after the field starts producing too much water/gas and oil production decreases. Effective EOR methods target both pore scale recovery as well as large scale field (vertical and areal) sweep efficiency. The choice and effectiveness of EOR methods depend on the oil and reservoir rock properties. The goal of this research is to optimise nanoparticle enhanced waterflooding for conventional oil recovery using the offshore Newfoundland oil fields as case studies. This work is important to the sustainable and increased production of Canada's conventional oil and our resource based economy.Laboratory research has shown that nanoparticle enhanced waterflooding, a type of chemical EOR, may be effective because the nanoparticles may alter the interfacial tension between the water and residual oil, and the nanoparticles may alter the wettability (contact angle) of the rock. One challenge is forming a stable nanoparticle-water solution in brine water (varying salinity) at reservoir conditions. Nanoparticles may also adsorb to the rock surface. This may have a positive or negative impact depending on whether wettability of the rock is changed favourably. Also, if the nanoparticles preferentially adsorb to the rock, they may not be available to decrease the interfacial tension between the water and oil.This research will systematically examine the use of different commercially available nanoparticles for EOR at reservoir conditions. We will investigate the stability of the nanoparticle-brine solutions over a range of reservoir conditions. The interfacial tension of the nanoparticle enhanced brine and oil as a function of nanoparticle type, concentration, water salinity, and oil composition, temperature, and pressure will be determined using the pendant drop method. We will examine the wettability (contact angle) as a function of nanoparticle adsorption on the rock based on the mineralogy and nanoparticle type. Having characterised the fluid-fluid and fluid-rock properties, we will use two types of laboratory scale reservoirs (micromodels and cores) to investigate and optimise nanoparticle enhanced waterflooding based on the fluid properties (salinity of the water, type and concentration of nanoparticles, injection rate, and volume) and reservoir properties (pore size distribution, permeability, and mineralogy) on the recovery of different quality (20-35oAPI) conventional oils.Through this research, we will screen and optimise nanoparticle enhanced waterflooding for practical and general field application (conventional oil in sandstone reservoirs) using offshore Newfoundland field conditions as a case study.