The stability of foam system is very important in the application of foam flooding and gas reservoir foam drainage agent. The influence of surfactant molecular structure and interface arrangement on the permeability and stability of foam liquid film is of great significance for the construction of highly stable CO

2

foam

but there is no systematic understanding at present. The beta

ine surfactant with four molecular structures is used as the research object

and the foam phase property evaluation is used as the research method. For the saturated adsorption capacity

foam liquid film permeability

foam stability and other phase properties

the surfactant molecular structure

interface arrangement

CO

2

foam liquid film permeability

foam stability and their correlation experiments are carried out. The results show that when the molecular head groups of surfactants are consistent

the hydrophobic carbon chain length increases

the hydrophobic effect increases

the molecules on the liquid film surface are arranged more closely

the permeability of foam liquid film decreases

and the stability of foam increases. When surfactant molecules have longer hydrophobic carbon chains

the enhanced hydrophobicity leads to a tighter arrangement of the liquid membrane and an increase in adsorption capacity

hindering the permeation behavior of CO

2

gas within the bubble and weakening the foaming ability of the foaming solution. Based on the regression analysis of the parameters obtained from four foaming systems

the correlation coefficient

R

2

between foam life

foam liquid film molecular adsorption capacity and foaming capacity and foam liquid film permeability

K

is established. The fitting shows that

R

2

0.90. Therefore

the permeability of foam liquid film

K

can be used as one of the parameters to evaluate the stability of foam system and provide a reliable evaluation parameter for the screening of highly stable foam system.