Research and application on foam plugged channeling system in high-temperature

aiming at the gas channeling problem in CO2 flooding in Zhongyuan oilfield, CO2 foam plugged channeling system with heat resistance and tolerance to salt was developed. The amphoteric surfactant imidazoline was selected to be foaming agent and copolymer TL3000 was foam stabilizer in this system. The evaluation results in laboratory showed that the prescription had excellent synthetically function: resistant temperature 100℃, salt tolerance 20×104 mg/L, calcium and magnesium resistance 5 000 mg/L. The formula was evaluated by CO2 gas inflation method, and the results showed that its half-life extends to 84 min, and surface tension is 30.6 mN/m while interfacial tension is 0.43 mN/m, and both of them are relatively lower. Visualization plugging experiment showed that this foam system has excellent foaming ability in porous medium. The core plugging test illustrated its strong plugged channeling ability with coefficient of resistance up to 25.63 and residual resistance factor of 9.4. 15 well times field application were launched, and the results indicated that the great plugging channeling capacity for CO2 gas channeling has provided a newly favorable attempt in controlling gas channeling problem in CO2 flooding.