空气悬浮法制备微胶囊延迟破胶剂的研究

RESEARCH ON PREPARATION OF MICROCAPSULATED DELAYED RELEASE GEL BREAKER WITH WURSTER FLUIDIZED BED PROCESS

采用空气悬浮法制备以过硫酸铵 (APS)为活性芯材料的压裂液微胶囊延迟破胶剂 ,设计了以乳液聚合方式合成的含氯化乙烯单体的三元共聚物为内层 ,以有机硅接枝改性的聚丙烯酸超微乳液和无机硅高分子材料为外层的体系 ,制成复合膜。可以通过改变膜层厚度、包衣乳液中助剂组成以及成品溶剂处理等方法调整胶囊的保护程度和释放行为。包衣材料回收率 90 % ,室温下水溶液中的初始释放率 <0 .5 % ,有符合应用需要的释放特性和化学、机械稳定性。 80℃下加入浓度为 0 .1 % (ω)的胶囊破胶剂的压裂液冻胶在 2h后仍可保持其初始粘度的 2 /3,与加入浓度为 0 .0 2 % (ω)的过硫酸铵的压裂液相比 ,岩心渗透性的伤害率由 2 5 .7%下降为 8.5 %。

The microcapsulated delayed release gel breaker of fracturing fluid was prepared by Wurst fluidized bed process using ammonium persulfate(APS) as active core material. The compound film was also prepared based on the ternary copolymer containing ethylene chloride monomer synthesized by emulsion polymerization as inner layer and polyacrylic acid extramicro emulsion modified by organosilicon grafting together with inorganic silicon macromolecular material as outer layer. The protecting extent and releasing behavior of the product can be adjusted by change of the thickness of the film layer, additive composition in coating emulsion,as well as the treatment of product with organic solvent.The recovery of coating material is 90%.The initial releasing ratio in aqueous solution of the product at room temperature is<0.5%,which possesses satisfied releasing specific property,chemical and mechanical stability. The initial viscosity of the fracturing fluid gel can keep at 2/3 of its original value when addition of 0.1% encapsulated gel breaker at 80℃ in 2 hours. The damage of core permeability drops from 25.7% to 8.7% compared with addition of 0.02% APS.