Abstract: CO₂ geological storage is an important technology to reduce CO₂ emissions, which can safely store CO₂ in geological formations for millions of years. Conventional CO₂ storage reservoirs include deep saline aquifers and depleted oil and gas reservoirs. Basalt is a new type of CO₂ storage reservoir that has been attracting attention in recent years. CO₂ storage in basalt would increase the technical method and potential of CO₂ geological storage. Storage potential assessment is one of the fundamental works of CO₂ geological storage study. This paper systematically examines the current methods for assessing the storage potential of CO₂ in basaltic rocks, and analyzes the principles and application scenarios of various methods. Then, the study takes the basalt of Icelandic Active Rift zone as an example to compare each of the methods. The study suggests that the current CO₂ mineralization storage potential assessment methods generally include three categories: ① Unit rock storage potential assessment method, which evaluates carbon sequestration potential based on the reaction volume or area of rocks; ② Mineral replacement storage potential assessment method: based on the volume of minerals that can react with CO₂ in basalts. ③Pore filling storage potential assessment method, which evaluates the proportion of secondary minerals that can fill reservoirs’ pore space after CO₂ mineralization. The authors note that the first method requires special experimental analysis, making it more challenging, the second method is more appropriat for basalts with high porosity and low reactive mineral content, while the third method is more suitable for basqlts with low porosity and high reactive mineral content.

Key words: basalt, CO2, geological storage, mineralization storage, storage potential, evaluation method