双生阳离子表面活性剂压裂液在煤层气井的应用

Twin cationic surfactant fracturing fluid applied to coalbed methane well

为了降低对煤储层的伤害,合成了一种双生阳离子表面活性剂和破胶剂,并优化形成了可控破胶的双生阳离子表面活性剂压裂液体系。研究结果表明：该表面活性剂链长度为传统单链表面活性剂长度的2倍,应用浓度与传统表面活性剂相比降低50%以上。该体系实现了低温下可控破胶,温度30℃下在2-8 h之内破胶液黏度达到3 m Pa·s,解决了表面活性剂压裂液破胶时间不可控制的难题。双生阳离子表面活性剂压裂液体系具有使用浓度低、造缝能力强、对煤储层伤害小（伤害率小于20%）、成本低、环境友好、可控破胶等特点,是适用于煤层气改造的压裂液体系,现场应用于65口井,均取得了较好的效果。

In order to reduce the harm to the coal reservoir,the twin cationic surfactant and gel breaker were synthesized and the controllable gel breaking twin cationic surfactant fracturing fluid system was optimized and formed.The study results showed that the chain length of the surfactant would be 2 times longer than the conventional single chain surfactant.In comparison with the conventional surfactant,the concentration of the twin cationic surfactant could be reduced by over 50%.The system realized a controllable gel breaking at a low temperature.Under the temperature of 30 ℃,the viscosity of the gel breaker would reach 3 m Pa·s within 2 - 8 h and an uncontrollable problem of the gel breaking time was solved for the surfactant fracturing fluid.The twin cationic surfactant fracturing fluid system with a low applied concentration,high fracturing capacity,less harm to coal reservoir（ harm rate less than 20%）,a low cost environment friendly,controllable gel breaking and other features was favorable to the fracturing liquid system of the coalbed methane reconstruction.The system was applied to 65 wells with a good effect individually.