Volume 56

Numerical Study of Sensitivity Analysis on CO2 Mineralization Sequestration in Basalt Reservoirs Geqi Zhai, Shuyang Liu, Qizhi Tan, Junrong Liu, Hangyu Li, Wenyue Sun

Abstract

CO2 mineralization sequestration in basalt reservoirs is an emerging and promising pathway for safe and effective CO2 capture, utilization and storage (CCUS), contributing to carbon neutrality. However, the mechanism of CO2 mineralization sequestration involves complex geochemical reactions, which are significantly affected by some factors. Mineral composition, temperature, pH, porosity, permeability and CO2 injection rate are important factors that influence CO2 mineralization in basalt, which require in-depth research and analyses. In this study, a radial model has been constructed using the multi-phase simulator GEM-CMG. This work focuses on the mechanisms of CO2 mineralization and how these mechanisms affect the efficiency of CO2 mineralization sequestration in basalt reservoirs. Sensitivity analyses are performed on the effects of injection mode (supercritical CO2 injection and co-injection of CO2 and water), injection rate and reservoir temperature on CO2 transport and mineralization in basalt reservoirs. The results suggest that more than 60% of the injected CO2 in basalt rocks mineralized within 450 days, and the majority of CO2 was sequestered as magnesite and siderite. Compared to the supercritical CO2 injection, co-injection of CO2 and water can enhance dissolution trapping and thus accelerate the mineral trapping process. In addition, the injection rate has a major influence on the extent of CO2-water-basalt reaction, and the CO2 mineralization efficiency increases with the decrease of the injection rate. Within reasonable limits, higher reservoir temperature is more favorable to efficient CO2 mineralization. This study is of great significance for the understanding of CO2 mineralization mechanism in basalt reservoirs and provides valuable insights for optimizing CO2 mineralization processes.

Keywords CCUS, CO2 mineralization, basalt, numerical simulation