Comprehensive evaluation method for site selection of CO2 geological sequestration in injection-level reservoirs

Geological sequestration of CO2 is a crucial means of reducing CO2 emissions. China in CO2 sequestration have commenced relatively late, and both site selection criteria and evaluation methods require further refinement. Primary sequestration sites for CO2 include reservoirs, coal seams, and deep saline formations. Among these, reservoirs serve as sequestration sites due to their favorable geological conditions, high degree of exploration, and potential for economic benefits. Currently, China categorizes sequestration sites into five levels: regional, basin, target area, site, and injection. This paper proposes a site selection and evaluation methodology specifically for the injection level. Firstly, a prediction model for the geological sequestration potential of CO2 in reservoirs is established based on machine learning methods. Subsequently, an evaluation index system is constructed based on three categories of indicators: safety, potential, and economy, the evaluation thresholds for potential indicators were determined using a potential evaluation model, while the evaluation thresholds for safety and economic indicators were established through methods such as factor analysis. Finally, a comprehensive evaluation method for the effectiveness of CO2 sequestration in reservoirs is formulated using the Analytic Hierarchy Process (AHP).