Multiscale PDE Modeling Of CO₂ Injection And Storage In The Niger Delta Basin: Integrating Geochemical Reactions And Probabilistic Risk Assessment

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🔬研究者:Provides a validated reactive transport model and sensitivity analysis methodology applicable to other sedimentary basins.

🏢実務担当者:Highlights fault-specific leakage risks and MRV priorities for CCS project operators and investors.

🏛政策担当者:Demonstrates the importance of pressure management and monitoring in CCS regulation and permitting.

Climate change continues to pose a critical global challenge, making carbon capture and storage (CCS) technologies central to efforts aimed at reducing anthropogenic CO₂ emissions. Among the most promising options is the use of deep geological formations in the subsurface as long-term storage reservoirs. This study provides a comprehensive appraisal of the CO₂ storage potential of the Agbada Formation (Central Swamp II, Niger Delta) under a pressure-limited injection strategy. A reservoir–reactive transport model, based on Darcy flow and advection–dispersion–reaction processes, was constructed and refined through grid convergence (Δx ≈ 10 m). The model was history-matched to Agbada pressure transients with good accuracy (RMS ≈ 3.4%) and validated geochemically against PHREEQC simulations, yielding mineral-volume deviations within 5%. To account for variability and reduce uncertainty, large ensembles (10³–10⁴ members) were employed, and global sensitivity analysis was conducted using standardized regression coefficients. In parallel, structural leakage likelihood was evaluated through fault-mapped simulations. The results indicate that CO₂ plume migration is strongly influenced by the presence of high-permeability corridors, while shale barriers effectively inhibit vertical communication. Maximum areal storage capacity is attained at depths around ~1,600 m, reaching ~5.56 Mt CO₂ km⁻². Sensitivity analysis reveals that permeability is the dominant control on plume radius (SRC ≈ 0.72), with nonlinear behavior becoming significant at values below ~50 mD. Importantly, a fault-localized leakage hotspot (F12) was identified, with simulated leakage rates exceeding the safety threshold by ~15%. The study underscores the importance of pressure-managed injection strategies and cautions against the assumption of linear superposition in multi-well storage projects. It further highlights the critical role of Monitoring, Reporting, and Verification (MRV) programs, particularly those focused on fault zones such as F12 and migration corridors where leakage risks are elevated. Future research directions should prioritize the integration of two-phase trapping mechanisms with hysteresis and gravity effects, the adoption of real-gas equations of state, and the inclusion of coupled porosity–permeability (k–ϕ) feedback to improve model fidelity. In addition, improved characterization of low-permeability corridors, step-rate injection tests, and interference-aware wellpattern design are recommended to optimize storage performance and reduce risks.

• semanticscholar https://doi.org/10.9790/0990-1402017383first seen 2026-07-20 05:42:02