Current status and development trends of CO2 storage with enhanced natural gas recovery (CS-EGR)

• Published in: Fuel (Guildford) 2023-10, Vol.349, p.128555, Article 128555
• Main Authors: Wang, Wendong, Wen, Jiayi, Wang, Chengwei, Gomari, Sina Rezaei, Xu, Xinyue, Zheng, Shuang, Su, Yuliang, Li, Lei, Hao, Yongmao, Li, Dongxia
• Format: Article
• Language: English
• Subjects: CO2 storage; CO2-natural gas displacement; Enhanced natural gas recovery; Gas reservoir; Storage mechanisms
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2023.128555

•The mechanisms of CSEGR are discussed in terms of CO2 injection for enhanced recovery and CO2 storage.•Reservoir permeability, CO2 injection parameters and perforation location are found to be the key factors affecting CSEGR.•More CSEGR experimental and simulation studies should be performed. CO2 storage with enhanced gas recovery (CSEGR) technology is a pivotal solution to mitigate the greenhouse effect and respond to national energy conservation and emission reduction policies. This involves injecting CO2 into gas reservoirs for storage and using it to displace gas into producing wells to enhance production. This paper provides a comprehensive analysis of the primary mechanisms of CO2 storage in gas reservoirs, quantifies the long-term contribution of these, and summarizes the methods used to evaluate CO2 storage potential. The mechanisms of the displacement of natural gas by CO2 are explained and two technical difficulties are addressed: the degree of CO2-natural gas mixing and competitive adsorption and displacement of CO2-CH4. Besides, the main factors affecting CSEGR are studied thoroughly, and the currently typical CSEGR field pilot tests across the word are considered along with CSEGR economic policy research. This paper then identifies the current challenges and future trends in CSEGR development. The results show, firstly, in the later stage of gas reservoir development, high rates of CO2 injection at the bottom of the gas reservoir and CH4 production at the top can significantly enhance gas recovery. Secondly, in previous studies, the degree of CO2-natural gas mixing has been studied more in sandstones and carbonates, while CO2-CH4 competitive adsorption has been studied more in shales and coal seams. The results of all these studies demonstrate the feasibility of CSEGR. Thirdly, Four major storage mechanisms interact to stabilize CO2 storage in gas reservoirs, but there is no systematic method to evaluate the CO2 storage potential. Finally, among recent experimental and simulation studies, CSEGR analytic techniques that consider complex formation conditions need to be further explored. Additionally, combining CSEGR with geothermal energy development in high temperature gas reservoirs presents a promising avenue for exploration.