Key Words:Non Newtonian flow;Carbon dioxide - Elasticity - Foams - Liquids - Rheology - Shear flow - Shear thinning;Co2 geological storages - Displacement mechanisms - Gaseous CO2 - Non-Newtonian behaviors - Pressure and temperature - Shear-thickening behavior - Supercritical CO2 - Supercritical CO2 (scCO2)
Abstract:Rheological properties of supercritical CO<inf>2</inf>(ScCO<inf>2</inf>) foam fluids are essential to understand foam displacement mechanisms in the research & development of efficient CO<inf>2</inf>-EOR and CO<inf>2</inf>geological storage technologies. In this paper, a systematic laboratory study concerning non-Newtonian ScCO<inf>2</inf>foam flow characteristics in a straight tube was carried out under different gas-liquid ratios. Through modifying experimental pressure and temperature conditions, comparative studies on liquid phase CO<inf>2</inf>and gaseous CO<inf>2</inf>foam rheology were also carried out. The experimental results show obvious shear-thickening behavior for the scCO<inf>2</inf>foam (45 °C and 8.0 MPa) with flow behavior index increasing from 1.03 to 1.76 with increasing foam quality. And the apparent viscosity of scCO<inf>2</inf>foam could reach up to 140 times of the single-phase water. The liquid phase CO<inf>2</inf>foam (25 °C and 8.0 MPa) also exhibits clearly the shear-thickening characteristics with flow behavior index ranging from 1.56 to 1.88. The gaseous CO<inf>2</inf>foam, on the other hand, behaves in a shear-thinning or pseudo-plastic manner with flow behavior index of 0.70 < n < 0.76. Due to the decreased interfacial tension and less bubble coalescence rate, much finer foam textures are observed for ScCO<inf>2</inf>and liquid CO<inf>2</inf>bulk foam, which mainly contributes to the shear thickening behavior for ScCO<inf>2</inf>and liquid CO<inf>2</inf>foam fluid.<br/> © 2018 Elsevier B.V.
Volume:164
Issue:无
Translation or Not:no