Foam Stability Influenced by Displaced Fluids and by Pore Size of Porous Media

Stability of foam in the presence of hydrocarbons is a crucial factor in the success of its use in various applications in porous media, such as soil remediation and enhanced oil recovery (EOR). It is generally believed that shorter-chain hydrocarbons with lower density and viscosity have more detrimental effect on foam stability than longer-chain hydrocarbons. However, it is still unclear how the pore size of porous media could influence this behavior. The main objective of the present study was to investigate the combined effect of the hydrocarbon chain length and hence the hydrocarbon's viscosity and pore size of porous media on the foam stability and its displacement efficiency. To this end, a systematic series of experiments was conducted using an empty Hele-Shaw cell and glass bead packs with different pore size. The results in the Hele-Shaw cell and with coarse and medium beads revealed that the lighter, less viscous oil (Isopar G) was more destructive to foam. However, the results in the fine glass bead pack experiments did not correlate well with this finding. In the fine bead pack, foam appeared to have higher displacement efficiency in the presence of the lighter, less viscous oil. Generally, our results suggest that the pore size of the porous medium plays a more important role on the foam displacement efficiency, compared to the type of oil.