Axisymmetric MATLAB-CFD Modeling of Near-Wellbore Thermal Fields During CO₂ Injection

Boundary conditions for flow transport and heat transfer coupled fully are applied to develop an axisymmetric Computational Fluid Dynamics (CFD) framework to study the evolution of transient thermal fields near the wellbore during CO₂ injection. The model captures and simulates temperature, pressure, velocity, and thermal gradients for the well-centric domain providing the ability to visualize and quantify cooling and cooling-front (and thermal gradient) localization. The response during the early stages of injection demonstrates that transient thermal conditions are principally controlled by the diffusion mechanism and, to a lesser extent, by adjunction. The reduction of pressure results in the cooling of the axial and radial cooling fronts and modifies the extent of the thermal response, for the whole injection period. The fields of extracted gradients and isotherms demonstrate that the risks associated with the transient thermal response are related to the peaks of the temperature gradients (rather than the absolute amount of temperature reduction), which for all the time were located at the wellbore wall and in the perforated interval, there were extremes of temperature. Further, the distribution of the coupled flow–thermal metrics (e.g., the intensity of advective heat transport) and the local Péclet number, clarify the division of the phases of injection regarding conduction-dominated and mixed advection–conduction transport. Analyses of time step sensitivity, numerical convergence, and independence of the mesh confirm the predictive thermal fields. Finally, scaling, with the use of dimensionless transport parameters and stability criteria of the gradients’ normalization, based on similarity in the Axisymmetric near well model CO₂ establishes a consistent pathway that provides field scale design guidance for CO₂ injection, and thermal integrity and rate control management.