论文详情
高温生物酶双元破胶性能与现场应用
油田化学
2019年 36卷 第3期
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Title
Field Application and the Performance of Biological Enzyme Double Breakdown Technology at High Temperature
作者
刘 彝
罗 成
李良川
吴 均
吴佐浩
颜 菲
但佳敏
Authors
LIU Yi
LUO Cheng
LI Liangchuan
WU Jun
WU Zuohao
YAN Fei
DAN Jiamin
摘要
针对高尚堡油田压裂液所用过硫酸铵(APS)破胶剂破胶不彻底、不均匀的问题,从海栖热袍嗜热菌中提取β-苷露聚糖酶的基因片断,通过凝胶色谱法和电喷雾离子化质谱分析了APS与生物酶的破胶原理,研究了苷露聚糖酶适宜的温度与pH值范围,用胍胶、生物酶和胶囊破胶剂及其他添加剂配制压裂液,在高尚堡深层水井进行了现场应用。结果表明,苷露聚糖酶为内切酶,通过内切作用大幅降低胍胶黏度与分子量,其直接作用于糖苷键,主要产生二~六低聚糖,单糖极少;而APS较易断裂糖环上的C—C键。β-苷露聚糖酶耐温120℃、耐受pH值 4~ 10.5,该酶最适宜的温度为 70℃、pH 值为 6~ 7,120℃下的活性为最高酶活的 40%,保持活性时间为 55min,90℃下的活性可保持180 min。在压裂液中同时加入APS和生物酶破胶,可降低残渣含量22%~ 45%。9口注水井压裂现场应用时,在压后裂缝完全闭合后,尾追高浓度生物酶溶液,现场增注效果良好,初期注水压力平均下降约13 MPa,平均累计增注1.2×104 m3,有效期290 d
Abstract
Aiming at the problem of gel nonuniform breaking using ammonium persulfate(APS)at fracturing fluid in Gaoshangpu oilfield,a gene fragment of β-mannan enzyme was extracted from marine thermophilous bacteria. The gel breaking principle of APS and biological enzyme was analyzed by means of GPC and electrospray ionization mass spectrometry. The proper temperature and the range of pH vale of β-mannan enzyme was researched. The fracturing fluid prepared with guar gum,biological enzyme,capsule breaker and other additives was applied in some deep wells of Gaoshangpu oilfield. The results showed that mannan enzyme was endonuclease. The viscosity and molecular weight of guar gum were greatly reduced by intersecting action which directly affected on the glycosidic bond and mainly produced 2—6 oligosaccharides with few monosaccharide. While APS preferred to break the C—C bond on the sugar ring. β-mannan enzyme tolerated 120℃ and 4—10.5 pH value. The optimum temperature was 70℃ and the pH value was 6—7. The enzyme activity at 120℃ was 40% of the highest enzyme activity,and the activity could maintain 55 min. While when the temperature was 90℃,the activity maintaining time increased to 180 min. Adding APS and biological enzyme into the fracturing fluid could reduce 22%—45% residue content. When the fracture was completely closed,the technology of injecting high concentration biological enzyme acquired effective stimulation in 9 fractured wells. The average injection pressure initially decreased about 13 MPa,the average cumulative injection quantity was 1.2×104 m3,and the validity was 290 days.
关键词:
破胶剂;
生物酶;
高温;
酶活;
低聚糖;
残渣;
Keywords:
gel breaker;
biological enzyme;
high temperature;
enzyme activity;
oligosaccharide residue;
DOI
10.19346/j.cnki.1000-4092.2019.03.003