Study On Evaluation Of Surface-active Polymer

Aiming at characteristics of oil reservoir in Pubei Oilfield and further enhancing the oil recovery ratio after the period of high-water-cut, performances of surface-active polymer were evaluated, and reasonable injection parameters and oil displacement effect were researched under the limit water-cut condition in lab.Through comparing with common polymer with medium molecular weight, it is found out that surface-active polymer has characteristics of low concentration, high viscosity and its viscosity is higher than common polymer with medium molecular weight. When surface-active polymers are prepared by fresh water, I surface-active polymer has better viscosifying action than III surface-active polymer; When surface-active polymers are prepared by produced water, III surface-active polymer has better viscosifying action than I surface-active polymer, and III surface-active polymer has good salt endurance and viscosity stability.The emulsification experiments shows:the emulsification capacity of III surface-active polymer is better than other polymers.Wettability changing effects are studied by dynamic contact angle measurement instrument, Laboratory experiments showed that III surface-active polymer can decrease wetting angle of cores and has good wettability changing ability.Interfacial tensiometer was used to evaluate performances of surface-active polymer on decreasing interfacial tension. It is found that III surface-active polymer is slightly better than I.Based on Displacement experiments, it is shown that the surface-active polymer has high coefficient of drag and residual resistance factor.Laboratory experiments indicated that when the size of surface-active polymer slug was 0.6PV, the displacement effect of surface-active polymer was better than that of common polymer, and the recovery of surface-active polymer increased more than 10% after water flooding. Combined with actual situation of low permeability in Pubei Oilfield, It is suggested that the viscosity 30mPa·s is chosen when the concentration of III surface-active polymer is 600 mg/L, the oil recovery reached 11.69% when the 0.6PV slug was injected.