A review of modeling approaches for CO2 injection into depleted gas reservoirs: Coupling transient wellbore and reservoir dynamics

Abstract

This paper reviews the current state of modeling the transient wellbore-reservoir coupling for CO₂ injection into depleted gas reservoirs (DGRs). It explores methodologies applied to CO₂ injection modeling, emphasizing recent advancements and unresolved challenges to provide an overview for researchers and industry professionals. A comprehensive perspective of the coupled wellbore-reservoir modeling system is offered, with detailed discussions on each aspect of the model including well modeling, reservoir modeling, wellbore-reservoir coupling schemes, and thermodynamic modeling. These components interact in complex ways during transient operations like injection start-up and shut-in. Inadequate modeling of these processes can lead to serious operational risks, such as wellbore damage from excessive cooling and inaccurate prediction of injection rates. Understanding these interactions is crucial for safe and efficient CO₂ storage operations. Future research should focus on developing more accurate two-phase wellbore models and addressing critical factors such as hydrate formation, as well as geochemical and geomechanical effects in the near-wellbore region, to enhance the accuracy of predictions for CO₂ injection into depleted gas reservoirs. The availability of real-world field measurements is essential for validating these models and improving their ability to predict complex transient behaviors effectively.