Assessment of CO2 mineral storage potential in the terrestrial basalts of China

Basalts contain a lot of carbon-fixing minerals which can achieve the fast mineral trapping of CO2. Based on the CO2 mineral trapping mechanism, an evaluation method for CO2 storage capacity in basalts was established, which considers two injection scenarios including direct CO2 injection and carbonated water injection. Then the geological conditions of terrestrial basalts in China were assessed. The range of CO2 mineral storage capacity in basalts at different probabilities was calculated by Monte Carlo simulation. The results show that the total theoretical mineral storage capacity of CO2 in the terrestrial basalts of China is 39792.05-54325.44 Gt with an average of 46948.36 Gt (P50). The effective mineral storage capacities for direct CO2 injection and carbonated water injection are 607.79-1121.44 Gt (P50 = 847.95 Gt) and 201.13-303.85Gt (P50 = 249.50 Gt), respectively. The corresponding effective storage coefficients at P50 are 0.0181 and 5.31 x 10-3, respectively. Carbonated water injection is advised for prior use, which can achieve CO2 mineral trapping more rapidly. The effective storage capacity is usually much larger than the CO2 emissions in the same region except for the eastern region, but their distributions are not well matched, needing a comprehensive source-sink optimization. The screening and classification of basalts in China should also be strengthened in the future to promote the utilization of CO2 mineral storage capacity and the implementation of demonstration projects.