Research advances on evaluation of CO2 geological storage potential in China

CCUS (Carbon Capture,Utilization and Storage) is a crucial technology that can be used to reduce CO2 emissions of electricity generated from fossil energy and industrial process. It plays an important role in China’s Carbon Neutral. CO2 geological storage is the key component of the CCUS which determines the development potential and development direction of CCUS. Therefore,establishing the evaluation method of CO2 sequestration capacity that suit for China’s geologic characteristic and estimating the CO2 storage capacity of China’s main basins are the foundation of the CCUS development in China. The evaluation of CO2 sequestration capacity was divided into four steps at abroad,named as country/state evaluation,basin estimate,site description,and site application,respectively. Considering geological characteristics,regional geology,assessment purpose,local protection,social health,the safety of storage and environment as key indicators for evaluation,a series of assessment indicator systems of basin estimate were established. Meanwhile,different calculation methods of CO2 sequestration capacity were put forward for different geological bodies of CO2 storage,such as CSLF (Carbon Sequestration Leaders Forum) method,DOE (United States Department of Energy) method,European Union method,and ECOFYS and TNO-TING method. The evaluation of CO2 sequestration capacity in China is in its infancy,that Unified and systematic evaluation method of CO2 sequestration capacity has not been established. The fuzzy comprehensive evaluation based on analytic hierarchy process was the main method used in CO2 sequestration capacity evaluation in China,and evaluation method of subsidiary basin estimate and solubility calculation method for CO2 sequestration capacity were put forward. China has huge potential and diversified geological bodies for CO2 geological storage,and Bohai bay basin,Songliao basin,Ordos basin,Jungar basin,Subei basin,and Sichuan basin are favorable areas for CO2 geological storage. Due to the complex geological conditions,the CO2 sequestration capacities of China obtained from different evaluation methods are to be a great discrepancy. Therefore,detailed assessment of CO2 sequestration capacity for means geological bodies urgently need to be carried out,including deep saline formations,being exploited and depleted oil and gas field,deep unminable coal seams,and shallow sea.