Rock-fluid interfacial tension at subsurface conditions: Implications for H2, CO2 and natural gas geo-storage

In H-2, CO2 and natural gas geo-storage, rock-fluid interfacial tension (gamma(rock-fluid)) is a key parameter which influences pore-scale fluid distribution and reservoir-scale gas storage capacity and containment security. However, gamma(rock-fluid) data is seriously lacking because of the inability to measure this parameter experimentally. Therefore herein, a semi-empirical method is used to calculate gamma(rock-fluid) at geo-storage conditions. Additionally, effects of organic acid and silica nanofluid on gamma(rock-fluid) are studied. The following results are obtained. gamma(rock-gas) decreases with pressure, temperature, organic acid concentration and carbon number increase, while gamma(rock-H2O) increases with organic acid concentration and carbon number increase; gamma(rock-gas) first increases and subsequently decreases with silica nanofluid concentration increase, while gamma(roc-H2O) first decreases and then increases with silica nanofluid concentration increase; for same thermo-physical and rock surface chemistry conditions, gamma(rock-gas) follows the order H-2 > CH4 > CO2. These insights provide pivotal guidance on gas geo-storage and thus aids in the implementation of a more sustainable energy supply chain. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.