生物酶破胶剂在气井压裂中的研究与应用

Research and Application on Enzyme Breaker of Fracturing in Gas Well

针对重庆合川区块气井压裂中常规氧化破胶剂如过硫酸铵(APS)存在的化学污染、破胶不彻底、返胶等问题,对生物酶破胶剂对该体系的破胶效果及适用性进行了研究。结果表明,生物酶破胶剂与该压裂液体系存在一定的配伍禁忌,但是通过添加0.06%酶保护剂,用30 mg/L生物酶+20 mg/L APS或50 mg/L或90 mg/L生物酶作破胶剂,体系均可彻底破胶,无返胶现象;使用1号瓜胶作稠化剂时残渣含量小于240 mg/L,分子量较小(在1 000～4 000 Da之间),完全满足施工要求。现场以生物酶与APS复配方式破胶的2口井压裂液返排率达63%以上,施工产能效果良好,压裂施工后测试产气分别为1.51×104m3/d和3.19×104m3/d。

A research on enzyme breaker for fracturing fluid used in Hechuan Chongqing,to replace conventional breakers,such as ammonium persulfate (APS).The experimental results show that the enzyme breaker is not compatible with fracturing fluid of Hechuan,however,by using 0.06% enzyme preservative agent,with the formulation of enzyme (30 mg/L or 50 mg/L or 90 mg/L) and APS (20 mg/L),the fracturing system can be broken down,furthermore,by using No.l guar gum as the thickener the residue is less than 240 mg/L.In application,the breaker that is compounded by enzyme and APS is used for two wells,the fracturing fluid flow-back rates are over 63%,and the each gas output is 1.51×104 m3/d and 3.19×104 m3/d.