Application of Cold CO₂ Injection in High Skin Factor Depleted Reservoirs: A Review

Subsurface storage of carbon dioxide (CO₂) in geological media is now an effective strategy to address the climate change issue. Upon CO₂ injection, thermal, hydrological, mechanical, and chemical processes take place in a storage media which may affect the storage performance. Specifically, the subsurface thermal changes during CO₂ injection impact bottom hole pressure, stresses, fracture initiation, and thus, well-bore characteristics. Depleted reservoirs with a high skin factor can pose significant operational complications in achieving favorable CO₂ injectivity. Keeping in view the thermal stress, and the usage of CO₂ in a very cold CO₂ state in the early stage of storage, the concerns of stimulation can be mitigated, offering the benefit of improved injectivity. This work aims to provide a comprehensive overview of CO₂ utilization and storage in high-skin factor-depleted reservoirs. Firstly, we will introduce the physical properties of CO₂. Next, we will present storage operational aspects and challenges related to injectivity. Moreover, we will shed light on an overview of depleted reservoirs and the factors that contribute to a high skin factor, along with its quantification. Finally, we will discuss the role of very cold CO₂ injection in high skin factor-depleted reservoirs to overcome injectivity challenges. In short, this review aims to summarize the striking developments in subsurface CO₂ utilization and storage in challenging reservoirs, thereby helping to de-risk the injection operation.