Interfacial tension and contact angle in CO2‐water/nanofluid‐quartz system

Abstract

AbstractNanoparticles can modify the interface properties that are critical for fluid flow in porous media. The interfacial tension (IFT) between CO2 and water and the contact angle (CA) of a water droplet on a mineral surface under high CO2 pressure are critical parameters for CO2‐related applications such as CO2 geological sequestration and CO2‐enhanced resource recovery. This study investigated the IFT and CA in a water‐CO2‐quartz system and a nanofluid (water including either Al2O3 or TiO2 nanoparticles)‐CO2‐quartz system. The values of the IFT and CA were obtained by axisymmetric drop shape analysis (ADSA) for a droplet on a quartz surface in a chamber pressurized with CO2. The effect of nanoparticles on the IFT and CA was explored by comparing the values for the pure water‐CO2‐quartz system. In addition, the effect of CO2 adsorption onto the substrate on the wettability was investigated. The results show that the values of the IFT decrease with increasing CO2 pressure, and the addition of nanoparticles to pure water lowers the IFT further (∼up to a 40% reduction in the liquid CO2 pressure range). The de‐wetting phenomenon was observed for both gaseous and liquid CO2 conditions. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd.