MCB系列微胶囊破胶剂的性能

Properties of the MCB series Microcapsule Gel Breaker

为解决水平井分段压裂过程中前段压裂液快速破胶的问题,以过硫酸铵为破胶剂,采用乳液聚合法合成2种具有不同囊衣结构的微胶囊破胶剂。测定了微胶囊破胶剂的有效含量、包埋率、释放速率及延迟破胶效果。实验结果表明,MCB-1、MCB-2两种微胶囊破胶剂的有效含量分别为38.56%和39.69%,包埋率分别为83.85%和85.89%。与普通市售包蜡胶囊破胶剂相比,该微胶囊破胶剂的释放速率较慢。延迟破胶实验表明,微胶囊破胶剂可以在4 h内保持压裂液的黏度缓慢降低,最终破胶后压裂液的黏度小于10 m Pa·s,显示出良好的延迟破胶性能,且对地层渗透率的伤害率小于12%。

In segmented fracturing of horizontal wells, gels of the fracturing fluids are often broken too early for the fluids to function properly. To solve this problem, two micro capsule gel breakers, MCB-1 and MCB-2, with different capsule cloths have been synthesized through emulsion polymerization, using ammonium persulfate as the core. The active contents, percent of encapsulation, rates of release and gel breaking retardation have been measured in laboratory experiments. The active contents of MCB-1 and MCB-2 are 38.56% and 39.69%, respectively, and the rates of encapsulation of MCB-1 and MCB-2 are 83.85% and 85.89%, respectively. Compared with the commercially available encapsulated gel breakers, MCB-1 and MCB-2 have comparatively slow release rates. The experiments also show that MCB-1 and MCB-2 gradually reduce the viscosity of the fracturing fluid in 4 hours, and the viscosity of the fracturing fluid after gel breaking is less than 10 mPa-s, indicating that the synthesized micro capsule gel breakers are effective in slowing down gel breaking, and the impairment of formation permeability caused by these gel breakers is less than 12%.