High Water Foam System And Its Performance

Foam flooding has been researched more than 30 years in the study of EOR, it was used in the field, and obtained a stated effect. But the reports about high salt and temperature-resistant oil displacement form system is very poor. This paper is aiming at researching the high salt and temperature-resistant oil displacement form system under the bad field conditions.Foamer and foam stabilizer have been selected by a great deal of experiments in this paper. The salt-resistant capability of foam system was improved remarkably because of the composite foam stabilizer. Two kinds of products with excellent high salt and temperature-resistant have been achieved, aiming at the system with composite foam stabilizer which are made up of the HXYP polymer and the YPA polymer. Examining the foam capability affected by NaCl, CaCl2, temperature, oil, and pH, and mensurating the long-term thermal stability of high-salt foam system. Investigating the rheological property and viscoelasticity of foam system by HAAKE rheometer; studing the foam system-oil interfacial tension in different salinity by using hanging drop meter; and researching the microstructure of foam systems which have salt and no salt by SEM. Under the field conditions, researching the oil displacement efficiency affected by the injection methods and the efficiency of the foam.The experimental result indicating, the foam quality of the foam systems which the salinity is 0, 18.25×10⁴mg/L, 20.3×10⁴mg/L are 70%, 69%, 68%; and the HL are 50.3min, 87.0min, 59.7min at 80℃. The foam system is of excellent characteristics when the concentration of sodium chloride/calcium chloride or salinity is 22 × 10⁴mg/L, 6×10³mg/L, 22.4×10⁴mg/L respectively at the same time the temperature is 80℃. And the composite foam stabilizer foam system has more excellent characteristics when the salinity is in a concentration. When the salinity is 18.25 ×10⁴mg/L or 20.3 × 10⁴mg/L the temperature-resistant capability of foam system is 90 ℃. When pH change from 4.1 to 10 foam system with high salinity is very stabilized. The oil-foam interaction is a little. The foam fluid puts up the characteristics of pseudoplastic fluid and excellent viscoelasticity. The system-oil interfacial tension can be reduced to 10^-2 mN/m. High concentration salt,surfactant and polymer formed a composite membrane with high strength, so the stability of foam is increased. The viscosity retension percent of foam system which salinity is 18.25 × 10⁴mg/L and 20.3×10⁴mg/L is 93% and 92.2% respectively, at the same time, system-oil interfacial tension is low, all these educe foam system is of excellent stability. Alternate injection with gas and...