| Deep and low-permeability unconventional oil and gas reserves and production increases and old oilfields resume production and production have become new directions.Existing mining methods cannot meet the needs of increasing production and recovery.On the basis of the effective enhanced oil recovery of polymer microspheres for control and flooding,the technology of preparing microspheres by inverse microemulsion polymerization has recently been developed,and the remarkable deep control and flooding effect has attracted widespread attention.However,there are also problems in the application of microspheres,such as the emulsifier used,the difficulty of recycling the oil phase,the easy waste and the uneven dispersion of the aqueous solution of the microspheres.Therefore,in this paper,the phase transition component method was used to successfully convert the system after inverse microemulsion polymerization into an O/W polymer nanocomposite emulsion with better dispersibility,so that the oil phase and emulsifier of polymer microspheres can be used.In addition,in order to improve the temperature resistance of polyacrylamide(PAM)nanospheres,an in-situ copolymerization reaction of acrylamide(AM),sodium p-styrene sulfonate(SSS)and modified montmorillonite(OMMT)was designed to prepare anti-Warm monomer SSS copolymerized P(AM/SSS)microspheres(PAS microspheres)and P(AM/SSS/OMMT)microspheres with OMMT(ASO microspheres).The main work and results obtained are as follows:(1)First,MMT was modified with CTAB,and the interlayer spacing was expanded from 1.23 to 2.01 nm to obtain OMMT,and then three different types of polyacrylamides were prepared by inverse microemulsion polymerization.The microspheres were tested by laser particle size analyzer,transmission electron microscope,thermogravimetric analyzer,etc.The results showed that the particle sizes of the synthesized PAM microspheres,PAS microspheres and ASO microspheres were all about 80 nm,and ASO with OMMT and SSS was added.The microspheres have the strongest temperature resistance,and the three nano-scale polymer microspheres have good monodispersity and no obvious agglomeration,and the expansion rate of the three polymer microspheres in aqueous solution after24 hours is about 100 times of the initial particle size.,has good swelling performance;(2)Secondly,the emulsion system after three different inverse emulsion polymerization is directly converted into O/W polymer nanocomposite emulsion,using nanometer particle size potentiometer,interfacial tension meter,electron microscope and other instruments After analysis,it can be seen that the particle size of the polymer nanocomposite emulsion is in the range of 40-70 nm,the interfacial tension is reduced,the temperature resistance can reach more than 90 ℃,and it can be stored for more than 30 days,and all have good salt resistance;(3)Finally,because the polymer nanocomposite emulsion system contains nano-scale polymer microspheres,oil-in-water nanoemulsion,and emulsifier,which have both the functions of profile control and oil displacement,two polymer nanocomposite emulsions are selected for low permeability.Core flooding,designed flooding experiments,and concluded from the flooding experimental curve that compared with water flooding,PAM nanocomposite emulsion improves oil recovery by 8.3%,while ASO nanocomposite emulsion improves oil recovery by9.7%,which verifies Such polymer nanocomposite emulsions have good application prospects in enhancing low permeability oil recovery. |
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