Abstract:
Objective The foaming agents were prepared by the combination of betaine LHSB with short carbon chain length and betaine OHSB with long carbon chain length in different proportions at high temperature and high salt (90 ℃, 25×104 mg/L) conditions, which were optimized to obtain a foam system with good plugging performance.
Methods The foam properties of different foaming agents were evaluated by Waring stirring method, and the synergistic mechanism of the foam was discussed by rheometer. The plugging effect of different foaming systems in porous media was investigated through core experiment.
Results The composite foaming agent S11 made from 0.2% LHSB and 0.2% OHSB has good foam properties, the foaming volume is 345 mL, the half life of defoaming is 132 min, and the performance of this foaming agent is 3 times higher than that of LHSB foaming agent. The core test shows that the drag coefficient and residual drag coefficient of S11 foam are 91.6 and 14.9, respectively.
Conclusions When OHSB is added in LHSB as stabilizer, the composite foaming agent can exhibit the characteristics of viscoelastic surfactant, which can reduce the drainage speed, improve the liquid film strength, and show synergistic effect in foam stability.
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