Study on Competitive Adsorption and Displacing Properties of CO₂ Enhanced Shale Gas Recovery: Advances and Challenges

Table 2

Physical properties and molecular parameters of CO₂ and CH₄ [104].

Property	CO2	CH4	Reference
Molecular mass, (g/mol)	44	16	—
Critical temperature, (K)	304.2	190.5	[74, 75]
Critical pressure, (MPa)	7.4	4.6	[74, 75]
Critical density, (kg/m^3)	467.6	162.7	[105]
Adsorbed phase density, (kg/m^3)	1028	372	[74, 75]
Molar polarizability, (cm^3/mol)	7.34	6.54	[106, 107]
Kinetic diameter, ()	3.30	3.80	[74, 75, 96]
Collision diameter, ()	4.00	3.82	[96]
Effective molecule diameter, ()	3.63	3.81	[96]