Synergistic enhancement in foaming performance of alkyl disulfonate/amine oxide compound system
In order to improve the foam performance of surfactants in oil reservoirs with harsh conditions of high-temperature and high-salt,binary surfactant systems were prepared from combination of sodium dodecyl diphenyl ether disulfonate(DDBS)and cocamidopropyl amine oxide(CAO),of which the best binary surfactant system with n(DDBS)∶n(CAO)=6∶4 was used to further synthesize the foam channeling agent(SHY-1).The binary surfactant systems were analyzed for their critical micelle concentration(CMC),surface tension at this CMC(γCMC)and foam properties via Roche foam meter and surface tensiometer,while SHY-1 was evaluated by high temperature and high pressure foam device and automatic core displacement device.The results showed that the interaction parameters of the binary surfactant system between monolayer and micelle were ranging from-3 to-7,showing a moderate strength of synergism.Compared with that of single DDBS and CAO,the CMC of the binary surfactant system was reduced by 87%and 64%,the surface tension was reduced by 12%and 15%,respectively,while the saturated adsorption capacity was increased by 136%and 57%.SHY-1 displayed a wide salinity adaptation range and good foam performance when the salinity was≤158308 mg/L and the mass concentration of Ca2+or Mg2+was≤10000 mg/L.Under the condition of 105℃and 15 MPa,the apparent viscosity of the foam generated in the central position of the porous media with a mass concentration of 2500 mg/L SHY-1 reached 180 mPa·s.
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