Numerical Simulations of Choked Flow Generation in Micro-fractures (CO2, H2O, and CO2-H2O Mixture Flow)

In geologic media with wide range of temperature and pressure environments, fluids can exist in gas, liquid, and supercritical phases, which develop multicomponent and multiphase fluid system. Geological CO2 sequestration also can generate such fluid system. While injected CO2 migrates to the brine through micro-pores or geologic fractures, the topology of the fractures can constrain the thermodynamic properties of the fluids. Particularly, fluid velocity can be faster than the sound speed of fluid in converging-diverging fractures where the choking condition and shock waves can be generated at the nozzle throat. In these simulations, the occurrence of shock wave and choked flow were simulated when CO2, H2O and their mixture were injected into the simplified converging-diverging fracture