Comprehensive feasibility analysis of carbon dioxide hydrate sequestration: A numerical study based on horizontal well networks

Carbon dioxide sequestration is a crucial strategy for achieving carbon neutrality. This study explores a novel approach to carbon dioxide storage in marine environments in the form of hydrate, addressing the stringent site requirements of traditional geological storage methods. Using a custom-developed simulator, a conceptual model for carbon dioxide sequestration in subsea reservoirs under a horizontal well network configuration was constructed. Key factors, including seawater depth, injection depth, and well spacing, were analyzed through simulations to quantify carbon dioxide storage capacity and assess associated risks under various sequestration scenarios. The results indicate that increasing seawater depth boosts both CO₂ storage capacity and safety, while deeper injection enhances safety but reduces hydrate storage capacity and raises leakage potential. Closer well spacing improves early-stage safety but increases long-term risks. The study outlines distinct sequestration stages and provides detailed analyses of CO₂ migration and phase transformations over time, contributing insights for advancing CO₂ sequestration strategies. • A model for CO₂ hydrate sequestration in a horizontal well network was developed. • The CO₂ hydrate sequestration process over time was divided into distinct stages. • A quantitative assessment of CO₂ storage and leakage risks was conducted.