Assessment of carbon dioxide storage potential in Deccan basalts using geophysical methods

Continental flood basalts are increasingly viewed as promising geological reservoirs for carbon dioxide (CO2) sequestration because of their ability to react with injected fluids and convert CO2 into stable carbonate minerals, offering permanent and leakage-free storage. Among them, the Deccan Volcanic Province (DVP) of India—covering nearly 500,000 km2—is one of the largest on Earth and holds significant potential as a carbon sink. In this study, we provide the first geophysical driven assessment of CO2 storage potential in the Deccan Syneclise and Narmada basins by integrating 12,072 line-km of 2D seismic data with borehole and core information from the Koyna–Warna and Killari regions. Seismic interpretation and map-based volumetrics indicate a gross rock volume of 88,937 km3 at depths greater than 750 m, the minimum threshold for achieving supercritical CO2 conditions. Petrophysical analysis highlights strong heterogeneity, with porosities ranging between 6 and 11% and an average net-to-gross ratio of ~19%, pointing to the importance of vesicular and amygdaloidal flow tops as primary storage intervals. Applying a storage efficiency factor of 40.65 kg/m3 (from Columbia River analogues) and conducting Monte Carlo simulations, we estimate a storage potential of 41–76 Gt CO₂, with P10 ≈ 43 Gt, P50 ≈ 58 Gt, and P90 ≈ 74 Gt. These results refine earlier broad estimates and establish a more realistic baseline for evaluating the Deccan basalts as a strategic component of India’s carbon capture and storage portfolio, supporting its long-term climate mitigation and net-zero ambitions.