提高采收率用聚(N-羟甲基丙烯酰胺-丙烯酰胺)微球的反相微乳液聚合及其性能

以煤油为连续相,50.0wt%N-羟甲基丙烯酰胺(N-MAM)、丙烯酰胺(AM)单体水溶液为分散相,Span80/OP-10为乳化剂,依据拟三元相图配制了含50.6wt%油相、42.0wt%水相、7.4wt%Span80/OP-10(质量比6∶1)乳化剂相的W/O微乳液(质量分数)。以N,N-亚甲基双丙烯酰胺(MBAA)为交联剂,在65℃过硫酸铵(APS)引发下进行反相微乳液聚合制备了纳米级交联P(AM/NMAM)微球。以微球粒径及溶胀性为考察指标,从单体配比、交联剂用量、引发剂用量及搅拌速率等方面对合成条件进行了优化。结果表明,在单体配比m(AM)∶m(N-MAM)为4∶1,交联剂MBAA用量0.60wt%、引发剂APS用量0.50wt%(以单体总质量计)、搅拌速率1000r/min的条件下合成的微球耐盐性好、吸水倍率高,在1.0×10~5 mg/L模拟地层水中可达18.40g/g。扫描电子显微镜(SEM)、透射电子显微镜(TEM)对微球形态的表征结果显示,其具有较好的球形度及单分散性,粒径分布均一,约为100nm左右。流变及岩心封堵实验表明微球胶乳具有良好的注入性,封堵效果显著,可实现逐级深部调剖。

Inverse Microemulsion Polymerization and Performance Study of Poly (N-Hydroxymethyl Acrylamide-co-Acrylamide) Microspheres for EOR

Using kerosene as the continuous phase,50.0wt％ aqueous solution of N-hydroxymethyl acrylamide and acrylamide as the dispersed phase,and a blend of surfactants (Span80/OP-10) as emulsified system,an inverse microemulsion was prepared according to the best aggregation point of kerosene (50.6wt％),aqueous phase (42.0wt％),Span80/OP-10 (7.4wt％,weight ratio 6∶1) based on the pseudo-ternary phase diagram.P(AM/N-MAM) nanoparticles cross-linked with N,N-methylene bisacrylamide (MBAA) were synthesized via the inverse microemulsion polymerization technique initiated by ammonium persulfate (APS) at the temperature of 65℃.Effects of the mass ratio of acrylamide and N-hydroxymethyl acrylamide,the amount of crosslinking agent,initiator and stirring speed on particle size and swelling properties of the microspheres were investigated.Under the optimal synthesis conditions,thatthe mass ratio of AM to N-MAM was 4∶ 1,the amounts of MBAA and APS were 0.60wt％,0.50wt％,and the stirring speed was 1000r/min,the polymer microspheres have high equilibrium swelling ratio with an absorbency of 18.40g/g in 1.0 × 105 mg/L salt solution and fine salt tolerance.Morphology of the polymer microspheres was characterized by SEM (Scanning Electron Microscope) and TEM (Transmission Electron Microscope),and the results indicate that the microspheres have distinct spherical shape,monodispersity,and uniform distribution of particle size about 100nm.The rheological and core plugging experiments show that the polymer microspheres latex exhibits good injectivity,and effective plugging,so that in-depth profile control is achievable step by step.