摘要:
Styrene(St),methyl acrylate(MA)and acrylamide(AM)were used as reaction monomers,and azodiisobutyronitrile was used as initiator,the microemulsion plugging agent was synthesized by reverse microemulsion polymerization.The best condition of synthetic reaction were as follows:fixed the emulsifier ratio of span80:tween80 was 2:1,the mass ratio of St:MA:AM was 3:1:2,the total monomer concentra-tion was 25%,the amount of initiator was 2% based on total monomers mass,the reaction temperature was 60 °C,the reaction time was 4 h,the median diameter of the plugging agent was 125.5 nm,which meets the requirements of plugging the microcracks of shale;the decomposition temperature of nano plug-ging agent was about 290°C,and the thermal stability is good.After adding 3%of the plugging agent into the drilling fluid system,90 °Chot roll 16 h,the viscosity and shearing force changed little and the rheo-logical property was stable,and the loss of API was only 2 mL,its FLHTHP(30 min)was 6.0 mL.The nano plugging agent had excellent performance and good plugging effect.%以苯乙烯(St)、丙烯酸甲酯(MA)和丙烯酰胺(AM)为反应单体,偶氮二异丁腈为引发剂,采用反相微乳液聚合法,合成了成膜型纳米微乳液封堵剂.合成反应的最佳条件为:乳化剂复配比span80:tween80=2:1(质量比),反应单体配比为St:MA:AM=3:1:2(质量比),单体总浓度为25%,引发剂用量为2%,反应温度60°C,反应时间4h.封堵剂的粒径中值为125.5nm,满足对页岩微裂缝封堵的尺寸条件;热重分析表明,纳米封堵剂分解温度290°C左右,热稳定性好;在钻井液体系中加入3%的封堵剂,90°C热滚16h后,粘度和切力变化不大,流变性较稳定,且其API滤失量仅为2mL,FLHTHP(30min)为6.0mL,该纳米封堵剂性能优异,封堵效果好.