Abstract: To select foaming agents applicable to reservoirs with high temperature and salinity, foaming performance studies were conducted on alkyl diphenyl ether disulfonate (2A1), alpha olefin sulfonate (AOS), carboxymethyl polyoxyethylene alkyl ether (AEC10) and six betaine surfactants. The results showed that, 2A1, AOS and AEC10 had low foaming rate and poor foam stability; among betaine surfactants, the hydroxysulfobetaine with amide groups was high in foaming rate and the hydroxysulfobetainehas without amide groups was sound in foaming performance; among similar betaine surfactants, the surfactants with long carbon chain had good foam stability and the surfactants with short carbon chain had high foaming rate; the hydroxysulfobetaine with different carbon chain lengths was compounded to obtain compound foaming agents S11 and S12 with excellent foaming performance, and their thermal stability was evaluated; it was found that S11 with amide groups had better thermal stability at 110 ℃, and S12 without amide groups had better thermal stability at 130 ℃. The study results provide a theoretical guidance for the selection of foaming agents applicable to reservoirs with high temperature and salinity

Key words: reservoirs with high temperature and salinity, foaming agent, betaine, foaming rate, thermal stability