During the injection, due to significant changes in pressure and temperature conditions from wellhead and bottomhole of a CO2injector, and transient effects in pressure and temperature during start-up and shut-in, CO2may go through complex phase changes both in space and in time. This paper predicted the temperature and pressure variations in and around the wellbore in both steady-state and transient conditions by a two-dimensional radial wellbore flow model with considerations of CO2in injection well, fluids in annulus, surrounding rocks and the storage reservoirs. Transport and thermal behaviours of CO2and its impact on surrounding fluids and rocks are investigated by solving the mass equation, momentum equations and energy equations. Temperature profile of CO2in tubing variation with injection time and its impact on those of water in annulus and surrounding rocks are explored. The mechanism of the increment of CO2temperature along the tubing is investigated. Moreover, the transient well shut-in effects on the pressure and temperature profile of CO2are predicted. The results provide basis for risk mitigations related to potential icing at the wellhead due to cooling during sudden shut-in and restart of injection for offshore projects.
Ruan, B., Xu, R., Wei, L., & Jiang, P. (2013). Thermal modelling in and around a CO2injector. In Energy Procedia (Vol. 37, pp. 3283–3290). Elsevier Ltd. https://doi.org/10.1016/j.egypro.2013.06.216