超临界二氧化碳在水平偏心环空中的流动

Supercritical CO2 is new drilling and completion fluid with many advantages, and it's one of the basic research directions to study on the flow mechanism of supercritical CO2 in annulus. Flow model in horizontal eccentric annulus was established and solved to reveal the influence of displacement and eccentricity on flow characteristics, with consideration of the coupling correlation between physical properties of CO2 and flow field temperature and pressure. Based on eddy viscosity theory, the mechanism how eccentricity, displacement, temperature, pressure influence pressure loss was illustrated. The results show that, the influence of friction on pressure loss is larger than that of turbulent kinetic energy. The pressure loss increases with the increase of displacement and pressure or the decrease of temperature. The pressure loss increases at first and then decrease with the increase of eccentricity and the critical eccentricity is 0.8. While the physical properties of CO2 is similar, the influence of temperature on pressure loss is larger than that of pressure. The pressure loss of CO2 flow in annulus is only 48.3%~67.6% that of water, which validates the advantages of driiling and completion with CO2..