【摘要】 针对煤层气储层温度低、凝胶体系破胶不彻底以及返排困难的难题,探讨了生物酶作为压裂液破胶剂对储层伤害程度。实验选用了生物酶破胶压裂液、过硫酸铵破胶压裂液和模拟煤层水对储层煤样进行伤害,处理后煤样分别进行扫描电镜、气体渗透率和原始煤样气体解吸实验。实验结果表明:生物酶能够对侵入裂隙中的压裂液有效破胶,不影响储层的裂隙发育结构,改善孔隙内气体导流能力,提高储层的气体渗透率;生物酶破胶体系能够显著降低对原始煤样中吸附气自然解吸的影响,气体解吸率达到了95. 65%;生物酶降解产生二氧化碳的速率与破胶程度正相关;低温对酶活性影响较小,60℃内温度升高降解速率增大。可见生物酶作为煤层气开发压裂液破胶剂效果明显。更多还原

【Abstract】 Based on the difficulty that under low temperature gel was unable to break completely and flow back in coalbed methane( CBM) well,the damage degrees of fracturing fluid by bio-enzyme were studied. Reservoir coal samples were treated with bio-enzyme gel breaking fracturing fluid,ammonium persulfate [( NH4)2 S2 O8]gel breaking fracturing fluid and simulated coal seam water,and tested by scanning electron microscope( SEM),gas permeability instrument and original coal sample gas desorption experiment. The results show: Firstly,the bio-enzyme can break gel effectively on coal fracture surface,without effects on developmental structure and degree of reservoir facture,also it can improve the reservoir gas permeability by changing the gas diversion capacity; Secondly,adsorption gas in original coal samples can desorb naturally to 95. 65% by the effects of bio-enzyme; Finally,there is a positive correlation between the carbon dioxide gas liberation rate and gel breaking degree,the gas is useful for flow back,the low temperature has less impact on bio-enzyme activity,degradation rate will increase with temperature rising below 60 ℃. The study results show that bio-enzyme can be used as gel-breaker of fracturing fluid for CBM reservoir effectively.更多还原