Experiment on high pressure CO2foam stability of nonionic surfactants

Key words:  CO_2foam  nonionic surfactant  CO_2flooding  mobility control

Abstract:

The performance of nonionic surfactants (nonylphenol ethoxylate series) used as CO_2foam agents was investigated using a high temperature and high pressure foam visualization meter under different temperature, pressure and salinity conditions. The influences of the polymerization number of ethylene oxide (EO), temperature, pressure and salinity on foam performance were evaluated. The foam 's blockage and mobility control ability were also tested in sandpack flooding experiments and the results were compared with the corresponding results obtained from the foam visualization meter. The correlation between the comprehensive foam performance index tested by foam apparatus and resistance coefficient in displacement test was analyzed. The results show that the surfactant 's hydrophilicity increases with the EO numbers increasing, which can improve CO_2foam performance and foam 's stability. While the foam performance declines with salinity, pressure and temperature increasing. The displacement experimental results reveal some influences of surfactant 's molecule structure on its foam performance, which can provide guidance on designing and improving nonionic surfactants used as CO_2foam agents.