Study On Property Control Of Amphiphilic Polymers For Oil Displacement And Its Synergistic Mechanism

As a kind of polymer flooding agent,amphiphilic polymer has obvious advantage in performance compared with ordinary polymer.However,polymer system is polydisperse due to its technical characteristics.But the structure and performance characteristics of different molecular weight components and their influence on the performance of the whole system are not clear.To a certain extent,it limits the understanding of the properties of the amphiphilic polymer and the generation of new property control methods.In order to solve this problem,the performances of different amphiphilic polymers,their separated components and mixed systems of them were studied.Based on these studies,some new methods of performance regulation were established and the synergistic mechanism was revealed.The theory and practice of the amphiphilic polymer can be supplemented and guided in a new way.The type-S amphiphilic polymer with polyether segment as the hydrophobic group and the type-L amphiphilic polymer with alkane chain as the hydrophobic group were selected as the research object.First of all,two kinds of suitable separation methods were established.On this basis,the viscosities,rheological properties and emulsifying properties of different separated components and their mixed system were studied.Furthermore,the synergistic mechanism was revealed by the regulatory effect of ?-cyclodextrin,rheometer,molecular energy method,dynamic light scattering,multiple light scattering,opticle microscope,scanning electron microscope,laser particle size analyzer and interface tensiometer and then,a performance control method based on separated components was established.Furthermore,the change rule and mechanism of the properties of amphiphilic polymers with different kinds of hydrophobic groups and their mixed system were studied.Moreover,the performance control method based on combination of two kinds of amphiphilic polymers was established.In the end,the oil displacement efficiency of the different systems were evaluated.The results show that when the volume of ethanol reaches 5 times of the volume of polymer solution,7000 mg/L type-S amphiphilic polymer solution and 9000 mg/L type-L amphiphilic polymer solution can be separated into macromolecular component and small molecular component at 5?.The mass ratio of macromolecular component and small molecular component is 1:2.The molecular structures of the different separated components are similar,but the former one has larger molecular weight and the latter one has more hydrophobic groups.Compared with small molecular component,the viscosity enhancement property,viscoelasticity and emulsion stability of macromolecular component are stronger.Under the synergistic action of the macromolecular component and small molecular component,the structure of the original sample is improved,and the structural viscosity increases significantly.Likewise,the relationship between molecular structure parameters and performances were systematically expounded.On this basis,the performance of the solution and the emulsifying ability were effectively adjusted by changing the proportion of different components,and then the optimum composition was selected.The synergistic mechanism was also obtained.Through further study,the change regulation of the properties of the combination of type-S and type-L amphiphilic polymers were revealed,at that moment the optimum compound proportion and synergistic mechanism were both obtained.Additionally,the combination system has better temperature resistance,salt resistance,shear resistance and pH tolerance.Under the condition of the same viscosity and injection volume,compared with the original sample,the displacement pressures and oil recoveries of the composition optimization system and combination system are higher.