Influence Factors and Feasibility Evaluation on Geological Sequestration of CO2 in Coal Seams: A Review

The geological sequestration of CO2 in coal seams holds significant implications for coalbed methane development and greenhouse gas mitigation. This paper examines the principles, influencing factors, and evaluation methods for geological CO2 sequestration in coal seams by analyzing relevant domestic and international findings. Suitable geological conditions for CO2 sequestration include burial depths between 300 and 1300 m, permeability greater than 0.01 × 10–3 μm2, caprock and floor strata with water isolation capabilities, and high-rank bituminous coal or anthracite with low ash yield. Geological structures, shallow freshwater layers, and complex hydrological conditions should be avoided. Additionally, the engineering conditions of temperature, pressure, and storage time for CO2 sequestration should be given special attention. The feasibility evaluation of CO2 geological storage in coal seams necessitates a comprehensive understanding of coalfield geological factors. By integrating the evaluation principles of site selection feasibility, injection controllability, sequestration security, and development economy, various mathematical models and "one vote veto" power can optimize the sequestration area and provide recommendations for rational CO2 geological storage layout.