MEMA10耐低温复合酶活性与破胶性能

Activity and Gel Breaking Performance of a Low-temperature-tolerant Complex Enzyme MEMA10

尤 佳 刘金峰 杨世忠 牟伯中

YOU Jia，LIU Jinfeng，YANG Shizhong，MU Bozhong

为解决现阶段酶破胶剂在压裂液破胶应用领域中破胶效率低、 适应范围窄、 特别是难以适应低温领域破胶需求的问题， 研究了来源于肠杆菌 N18（Enterobacter sp. N18）的耐低温复合酶 MEMA10的组成及与压裂液的配伍性， 评价了该酶的破胶性能， 以及 pH值、 温度和盐浓度等对粗酶酶活和破胶效果的影响。结果表明， MEMA10以β-甘露聚糖酶为主， 同时含有葡聚糖酶为代表的纤维素酶类， 以及脂肽类生物表面活性剂， 可作为以植物胶为增稠剂的压裂液的破胶剂。MEMA10与压裂液中各项添加剂配伍性良好。在 pH 3.0数 8.0范围内， 破胶剂活性能保持在 75%以上； 在 20～ 60℃范围内均能在 3 h内将高黏度瓜尔胶压裂液的黏度降至 5 mPa· s以下； 在 1 mol/L和 2 mol/L的 NaCl长时间作用下， 酶活仍在 80%以上。40～ 60℃范围内， 压裂液经 MEMA10彻底破胶后的表、 界面张力以及残渣量均符合行业标准。MEMA10具有使用浓度低、 pH适应范围广、 耐盐、 低温活性强、 破胶残渣少等特点， 适应中低温压裂破胶的需求。图8表3参24

In order to solve the problem of low efficiency of enzyme breaker in fracturing fluid gel breaking，especially the problem that enzyme breaker was difficult to meet the needs of low temperature field gel breaking，the composition，the compatibility with fracturing fluid and the gel breaking performance of the low-temperature-tolerant complex enzyme MEMA10 from Enterobacter sp. N18 were studied. The effect of pH value，temperature and concentration of salt on enzyme activity was studied as well. The experiment results indicated that β-mannanase was the main ingredient in MEMA10，which contained cellulase and lipopeptide as well. The complex enzyme could be used as gel breaker in fracturing fluid which used gum as thickening agent. MEMA10 showed good compatibility with the additives of fracturing fluid. When the pH value was in the range of 3.0—8.0，the activity of MEMA10 retained over 75%. The viscosity of guar gum solution reduced to less than 5 mPa·s by MEMA10 at 20—60℃ within 3 h. The enzyme showed more than 80% of enzyme activity after incubating for a long time in the presence of 1 mol/L and 2 mol/L of NaCl. Meanwhile，the surface tension，interfacial tension and the amount of residues of fracturing liquid after a thorough gel breaking by MEMA10 at 40—60℃ all met the industry standard. MEMA10 met the needs of medium and low temperature gel breaking due to its low using concentration，broad working pH range，salt tolerance，strong activity at low temperature and low residues.

10.19346/j.cnki.1000-4092.2016.04.009