低伤害LMWF压裂液

A low damage frac fluid LMWF

介绍了一种低伤害LMWF压裂液,它用改性的低分子量瓜尔胶配成基液,经硼交联得到LMWF压裂液。该体系不用破胶剂,靠pH值变化自动破胶,因而减少了不溶性残渣,避免了对储层的伤害,提高了地层渗透率。对该体系的流变性、破胶性和再循环使用性的评价表明,该体系具有良好的携砂性能、长时间的流变稳定性;由于不舍破胶剂,LMWF压裂液稳定,能长时间泵送;当压裂作业完成后,pH值降低,当pH值低于8时低分子量聚合物凝胶的交联性能随即丧失.压裂液恢复到起始的低粘度,使LMWF压裂液能迅速彻底地从裂缝中返排。应用表明,LMWF压裂液对地层伤害小,携砂性能好,提高了产油量。该体系可循环使用,节约了成本,保护了环境。

A low damage fracturing fluid referred to as low molecular weight fracturing (LMWF) fluid was presented, which was prepared with modified low molecular weight guar gum as base fluid and boron as crosslinking agent.For there is no any gel breaker in the system and it breaks automatically with pH value changing, infusible residue producing and formation damaging are prevented and reservoir permeability is improved.The rheological properties, breaking mechanism and recycling ability of the system were evaluated and results showed that it has good properties of carrying cuttings and stability during pumping; as there is no gel breaker, it can be transported by pump in a stable regime for a long time; crosslinking property of the low molecular weight polymer keeps until pH value is less than 8 after fracturing, and that means the viscosity recovers to the initial low viscosity, thus the fracturing fluid can be discharged rapidly from fractures.Application showed that LMWF has strong carrying capacity with less damage to formation and oil production can also be increased.In addition, ?5 ?working cost can be reduced and environment can be protected for recycling the system.