Considering the special nature of CO2 and the behavior of CO2 foam in the porous medium different from foams of other gases

CO2 foam stability

decay property of CO2 foam and effect of partially hydrolyzed polyacrylamide (HPAM) on CO2 foam properties were studied. The gas-flow method was used for foaming and sodium dodecyl benzene sulfonate (SDBS) was used as the foaming agent. The stability of CO2 foam was worse than that of N2 foam under the same conditions and was nearly not influenced by surfactant concentration. Besides

the decay curve of CO2 foam was approximately a straight line and the volume of CO2 foam decreased rapidly after foaming. An important factor leading to the poor stability of CO2 foam lay on the large film permeability coefficient because of higher solubility of CO2 in water

which further led to the different propagation behavior of CO2 foam from N2 foam in the core. The adding of polymer HPAM enhanced the stability of CO2 foam to a certain extent

but reduced the foaming property of surfactant solution. Therefore

both foam stability and foaming property of surfactant solution should be considered to determine the optimal concentration of polymer in the actual application.