苏里格气田压裂返排液回用技术研究与应用

根据苏里格气田压裂返排液的特点和回用配制压裂液对水质的要求，形成了一套以“预处理—混凝沉降—两级过滤—杀菌抑菌”为工艺路线的压裂返排液处理技术。经处理后的返排液固体悬浮物小于20 mg/L，钙、镁离子含量小于30 mg/L，化学需氧量低于100 mg/L，配制瓜胶压裂液72 h黏度下降率低于20%。处理后的返排液用于配制瓜胶压裂液和聚合物压裂液，其耐温耐剪切性、黏弹性、破胶液性能等各项指标均满足行业标准要求。现场可对各个模块和处理单元进行选择性组合实现快速处理和精细处理，速度为150～300 m3/d。近3年使用处理后的返排液配制压裂液超过3.6×104 m3，应用效果良好。 

Research and Application of Fracturing Flowback Fluid Reuse Technology in Sulige Gas Field

According to the characteristics of fracturing flowback fluid in Sulige gas field and the water quality requirement of treated flowback fluid used to prepare fracturing fluid, a series of treatment processes including pretreatment, coagulation & sedimentation, double filtration and sterilization & inhibition, had been established. After treatment, the suspended solid in the flowback fluid could be controlled to less than 20 mg/L, the content of calcium and magnesium ions is less than 30 mg/L, and the COD is also be reduced to lower than 100 mg/L. Viscosity decreasing rate of the guar gum fracturing fluid prepared by the treated water is less than 20% after 72 h. The treated water is used to prepare both guar gum based and polymer based fracturing fluid, whose temperature and shear resistance, viscoelasticity and gel-breaking properties could meet the requirements of the general industry standards. Both rapid and fine treatment within a treating speed of 150~300 m3/d can be realized by selectively combining each module and processing unit. In the last three years, more than 36,000 m3 fracturing fluid were prepared by using the treated flowback fluid and the field application effect is remarkable.