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.