Simulation study of CO₂ geological storage in a tight sand reservoir with hydraulic fractured horizontal well

Carbon capture, utilization, and storage (CCUS) is a vital technology for reducing greenhouse gas emissions. While numerous studies investigate CO₂ storage in conventional geological formations, such as depleted oil reservoirs and saline aquifers, this study provides a novel assessment of CO₂ sequestration in a depleted oil and gas reservoir characterized by tight sandstone in British Columbia, Canada. Advanced numerical simulations evaluate the feasibility and challenges of CO₂ storage in low-permeability formations, focusing on its behavior in a hydraulically fractured horizontal well with 17 fracture stages. Unlike in conventional reservoirs, CO₂ exhibits limited migration, remaining concentrated in fractured zones and demonstrating enhanced storage stability. Over a 10-year injection period, more than 100,000 tons of CO₂ were successfully injected at a rate of 15,000 m³/day. The study also quantifies the contributions of various trapping mechanisms: residual trapping (10%), solubility trapping (2.9–14.3%, with the highest solubility under ideal conditions), and structural trapping (0.6%). These findings provide new insights into the potential and limitations of CO₂ storage in unconventional reservoirs, highlighting both the challenges and unique advantages associated with tight sand formations.