Laboratory study of the Non-Newtonian behavior of supercritical CO2 foam flow in a straight tube.

Rheological properties of supercritical CO 2 (ScCO 2 ) foam fluids are essential to understand foam displacement mechanisms in the research & development of efficient CO 2 -EOR and CO 2 geological storage technologies. In this paper, a systematic laboratory study concerning non-Newtonian ScCO 2 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 2 and gaseous CO 2 foam rheology were also carried out. The experimental results show obvious shear-thickening behavior for the scCO 2 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 2 foam could reach up to 140 times of the single-phase water. The liquid phase CO 2 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 2 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 2 and liquid CO 2 bulk foam, which mainly contributes to the shear thickening behavior for ScCO 2 and liquid CO 2 foam fluid. [ABSTRACT FROM AUTHOR]