Study On The Self-assembly Of ?-hydroxy Zwitterionic Hydrophobically Associating Polymer And Surfactant

In the process of oilfield development,the temperature and salinity of the reservoir are getting higher and higher.At this stage,the polymer such as partially hydrolyzed polyacrylamide(HPAM),the apparent viscosity of the solution lost a lot under high temperature and high salinity,so HPAM cannot meet the requirements of practical application.In order to be used in the oilfield,which have conditions of high temperature,high salinity and high shear rate,in this paper,a combination of ? hydroxy betaine type ionic hydrophobic associating polymer and surfactant was studied.The combination condition of the self-assembly system and its shear property and temperature sensitivity were studied.(1)The synthesis of four ?-hydroxy containing zwitterionic polymerizable monomer 1-(2-hydroxypropyl sulfo)-acrylamide ethy1-N,N-dimethyl ammonium chloride(MeSA),1-(2-hydroxypropyl sulfo)-acrylamide ethyl-N,N-diethyl ammonium chloride(EtSA),1-(2-hydroxypropyl sulfo)-acrylamide ethyl imidazole salt(ImSA),1-(2-hydroxypropyl sulfo)-2-acrylamido pyridine salt(PySA),and four kinds of monomers were copolymerized with acrylamide(AM),acrylic acid(AA)and hydrophobic monomer N,N-diallyl oleamide(DNDA)respectively.The synthesis conditions were optimized,and the structure of the hydrophobic associating polymer was characterized by IR,NMR and intrinsic viscosity.The results showed that the synthesized substance was the target copolymer.(2)And screened four best self-assembly systems by evaluate the surface tension and apparent viscosity of systems.The self-assembly systems,which we get,are AM/AA/DNDA/MeSA-Tween-40,self assembly system AM/AA/DNDA/EtSA-Tween-40,AM/AA/DNDA/ImSA-Tween-40 and self assembly system AM/AA/DNDA/PySA-Tween-40.At the same time,the optimal ratio of surfactant and polymer was evaluated as 1:2.(3)Rheological property of self assembling systems were evaluated by high temperature rheometer,and the effect of high shear rate on self assembly systems were examined,and when the shear rate of AM/AA/DNDA/PySA-Tween-40 system is 1000 s"1,the apparent viscosity of system is 29.8 mPa s;and it was found that,when the self assembling system in shear rate from 170 s-1 increased to 510 s-1,the apparent viscosity of self assembly system solution was essentially unchanged;in addition,the self assembly system has excellent viscoelastic properties,which can be applied to high shear rate.(4)Investigate the temperature sensitive effect of self assembly system.Study the change of apparent viscosity of self-assembled system in the temperature varies from 25 ? to 120 ?by use high temperature rheometer.Compared to the polymer solution,the apparent viscosity of self assembly system is no longer simply decreased,but there is a certain increase when the temperature reaches 80-110 ?.The main reason for this phenomenon is the fact that,for polymers,a rise in temperature to polymer in the aqueous solution curly arrangement,when adding a surfactant,comprising the hydrophobic chain under higher temperature help hydrophobically associating polymers formed more stable physical crosslinking force,and the apparent viscosity exhibit the thermo sensitive effect.At the same time,the self assembly system at 120 ? under constant temperature for a period of time,found that the apparent viscosity of self assembly system AM/AA/DNDA/MeSA-Tween-40 will appear certain rise.(5)The apparent viscosity of the self assembly system in the formation was evaluated.The apparent viscosity of the polymer is affected by the metal ions in the formation;the adsorption of the polymer in the formation affects its loss in the formation,thus affecting the apparent viscosity of the solution.The effect of sodium,calcium and magnesium ions on the apparent viscosity of self assembly system was studied,and it is found that the apparent viscosity of the self assembly system is satisfied with its application in oil field.Study self-assembly adsorption capacity of the system.When the adsorption time was 72 h,the adsorption amount of AM/AA/DNDA/MeSA-Tween-40 system was 0.26,The adsorption amount of AM/AA/DNDA/EtSA-Tween-40 and AM/AA/DNDA/ImSA-Tween-40 system were 0.27 and 0.29,the adsorption capacity of AM/AA/DNDA/PySA-Tween-40 system is 0.32.The study also found that the self assembly system AM/AA/DNDA/PySA-Tween-40 can enhance the oil recovery rate of 12.36%.According to the experiment results,property of zwitterionic copolymer and surfactant self-assembly system was illustrated.All of these results offer some important reference to self-assembly system investigated in the future.