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

Abstract 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.