高温生物酶破胶剂在克拉玛依油田压裂液中的应用

研究了用生物酶破胶剂来解决克拉玛依油田压裂液体系破胶不彻底、对地层伤害大这一难题的可行性。结果表明,调整生物酶用量至250 mg/L 和添加酶保护剂250 mg/L,并与0.01%过硫酸铵复配,2.5 h 可以彻底破胶,破胶液黏度为3.3 mPa·s,残渣量280 mg/L,且无返胶现象。质谱分析破胶液分子量集中在2 147~6 366 Da,主要为13~39 低聚糖分子,表明生物酶破胶剂将瓜尔胶彻底降解成小分子的多糖化合物,解决了破胶不彻底并返胶的难题。

Application of High-Temperature Enzyme Breaker to Fracturing Fluid in Karamay Oilfield

Karamay field fracturing fluid system occurs in the problems of incomplete guar gum breaking and oil layer damage. The study showed that the high-temperature enzyme breaker had incompatibility with additives of the Karamay fracturing fluid system. The fracturing fluid viscosity can be reduced to 3.3 mPa·s within 2.5 h by adding 250 mg/L enzyme breaker, 250 mg/L protective agent and 0.01% ammonium persulfate, and the residue of 280 mg/L, which meet the national standards of an oilfield. The molecular weight of the fracturing fluid was measured by mass spectrometry, which was mainly concentrated in the range of 2 147~6 366 Da, indicating that the enzyme breaker can be used to decrease the viscosity of fracturing fluid and degrades gum to oligosaccharides.