Molecular dynamics simulation of nanocellulose-oil-water interaction in enhanced oil recovery application

Abstract

Enhanced Oil Recovery (EOR) is a way to obtain long hydrocarbon-structured oil by flooding oil reservoirs using water with certain materials. Hydrolyzed polyacrylamides (HPAM) and xanthan gum are commonly used in the EOR process. Both of these materials have several disadvantages, including unstable at high salinity and leave debris in the environment. One alternative to substitute HPAM and xanthan gum is nanocellulose, which is an abundant amount of natural polymer. Molecular dynamics simulations investigate the potential of nanocellulose as an EOR agent. A mixture of decane and naphthalene is used as an oil model, while the SPC/E model is used as a water model. By analyzing the simulation trajectory, the interfacial tension and viscosity values were obtained. The simulation results showed the value of the water-oil interfacial tension increased with the addition of nanocellulose. This was caused by the position of nanocellulose that was always in the aqueous phase during the simulation. The water-oil interfacial tension also increased from 46.94 dyne/cm to 47.96 dyne/cm with the presence of two nanocellulose molecules at 353 K. Water viscosity increased from 3.10×10−4 kg/m.s to 3.80×10−4 kg/m.s after the addition of one cellulose molecule at 353 K. Nanocellulose can be an EOR agent by increasing the water viscosity but unfortunately the water-oil interfacial tension also increasing. Due to the change of these two opposing properties, nanocellulose cannot optimally improve oil recovery as shown by previous research.