Volume 51

Study on the Effect of CO2-Brine-Rock Interactions on Reservoirs during the CO2 Geological Storage Haiwei Zuo, Shenglai Yang, Yulong Dang, Qidong Lian

Abstract

Injecting CO2 into the reservoir can achieve geological storage of CO2 while improving recovery, which can effectively mitigate CO2 emissions. The balance between reservoir rocks and formation water is disrupted by the injected CO2, resulting in changes in porosity, permeability, and formation water characteristics as well as mineral corrosion and precipitation. These changes ultimately impact the safety and capacity of CO2 storage. In this paper, the CO2-Brine-Rock interaction mechanism and its effect on the reservoir are studied by using sandstone cores from the Qiuling Oilfield in China as experiment objects, through indoor core flooding experiment, nuclear magnetic resonance (NMR) experiments, and ion analysis of the reaction solution. The experimental results show that the porosity and permeability of the cores increased slightly after CO2 flooding, and the increase in porosity at the entrance is higher than that at the export; The content of Na+, Ka+, HCO3-, CO32- ions increase and the content of Mg2+, Ca2+, Ba2+ ions decrease in the final reaction solution. The results of this study provide theoretical support for further research on the CO2 capture mechanism and geological storage of CO2 in water-bearing reservoirs.

Keywords CO2 storage,CO2-Brine-Rock interaction,CCUS,nuclear magnetic resonance