Potential and research progress of CO2 geological storage based on deep coal underground gasification
WANG Weibin
LIU Shuqin
QI Chuan
LIU Yueming
YANG Ruizhao
JIANG Binbin
LI Jingfeng
Abstract：Deep coal underground gasification coupled CO2 storage(UCG-CCS)is a key technology to achieve clean coal development and carbon emission reduction.While improving the utilization rate of combustion cavity,the geological storage of CO2 has the characteristics of good injection,complex sealing,saving transportation cost and great storage potential,etc.,and has become a hot spot in CO2 storage research in recent years.In this paper,the research progress is systematically reviewed from four dimensions:mechanism research,stability evaluation,storage efficiency and leakage monitoring:① The depth and temperature of deep coal underground gasification combustion cavity are conducive to supercritical CO2 storage,and the high permeability of combustion cavity can ensure good CO2 injection;Gasification residue,ash and caved rock have adsorption and mineralization ability.The long-term interaction with the salt water layer in the combustion cavity is conducive to CO2 dissolution and storage.② The cavity tightness is affected by multiple factors,and is related to the thickness of the gasification coal seam,the width of the gasification surface,the width of the retained coal pillar,the depth of the formation and the geological structure,etc.The comprehensive design of the gasifier structure ensures the tightness;The CO2 injection pressure should be controlled to avoid breaking through the cap pressure.The long-term transport of CO2 geologic storage depends on the long-period numerical simulation and engineering observation.Injection Wells and production Wells are important ways of CO2 leakage.③ The storage capacity of underground coal gasification depends on the shape of the combustion cavity,gas production and gas production components.At present,an accurate CO2 storage capacity evaluation model for underground coal gasification and gas storage is urgently needed.④ Leakage monitoring and environmental risk assessment is an essential risk control link for engineering CO2 storage.CO2 storage requires long-term monitoring of surface deformation,wellbore leakage and pollutant migration,but faces challenges such as formation heterogeneity,high-temperature corrosion,signal attenuation,etc.,and needs to build a multiphase seepage model and environmental sustainability index evaluation system to ensure safety.
Keywords：deep coal underground gasificationcombustion cavityCO2geological storagestorage mechanism
Publication Date：2025-04-30
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：10( 14-23 )