Production of ultra-low interfacial tension between crude oil and mixed brine solution of Triton X-100 and its oligomer Tyloxapol with cetyltrimethylammonium bromide induced by hydrolyzed polyacrylamide

Aggregation behavior of mixture of polyoxyethylene tert-octylphenyl ether (TX-100) and its oligomer Tyloxapol with cetyltrimethylammonium bromide (CTAB) at the crude oil/water interface in the presence of hydrolyzed polyacrylamide (HPAM) was investigated via the interfacial tension (IFT) measurement by spinning drop technology at 70.0 °C in 10,000 mg L−1 brine solution. Effects of HPAM concentration and mass ratios of nonionic surfactant/CTAB on the dynamic IFT between crude oil and aqueous solution were studied in detail. For single surfactant systems, it was found that the ability of lowering IFT for CTAB was better than that for nonionic surfactant, while the IFTs yielded by system with Tyloxapol were higher than that yielded by the system with TX-100; and the IFTs obtained by mixed surfactants systems were always higher than that obtained by CTAB. Interestingly, the ultra-low IFT was obtained for all surfactant mixtures in the presence of HPAM, i.e., HPAM was as an inducer to produce the ultra-low IFT between crude oil and mixed brine solution of TX-100 and its oligomer Tyloxapol with CTAB. However, there existed both synergism and antagonism between HPAM and mixed surfactants on crude oil/water IFT reduction. Only when mass ratios of nonionic surfactant/CTAB and the amount of HPAM were appropriate could the ultra-low IFTs be obtained. And the difference between HPAM/TX-100/CTAB and HPAM/Tyloxapol/CTAB mixed systems in reducing IFT was that the time to reach ultra-low IFT was longer for the latter system. The result might be of real significance in the enhanced oil recovery (EOR).