| In this paper,in order to solve the problem of reinjection fracturing flowback fluid,a research was studied on the treatment of fracturing flowback fluid from a tight oil field in Xinjiang.The charaters of the fracturing flowback fluid was analized which showed as oil-in-water emulsified wastewater.The main pollutants were oil,suspended solids,and bacteria.The water quality saturation index SI>0 and the water quality stability index SAI<6 which showed the wastewater was easy to form scale.The treatment of fracturing flowback fluid was carried out by demulsificationcoagulation-purification process.The optimum additives and dosage were determined.The optimum dosages of the demulsifier,coagulant,coagulant aids,bactericide,scale inhibitor,corrosion inhibitor and sludge dewatering agent were 100 mg/L,1250 mg/L,5 mg/L,200 mg/L,100 mg/L,50 mg/L,80 mg/L and 30 mg/L,respectively.After the treatment of the fracturing flowback fluid,the suspended solid content was decreased to 18.3mg/L,the saprophyte bacteria(TGB)was decreased to 25/m L,the sulfate reduction bacteria(SRB)and iron bacteria(IB)were decreased to 0,the calcium loss rate was decreased to 2.49%,and the corrosion rate was decreased to 0.0097mm/a.The treated fracturing flowback fluid met the reinjection standard of “SY-T 5329-2012 Recommended Index for the Injection Water Quality for Clastic Reservoir and its Analyzing Method”.Field test of fracturing flowback fluid reinjection was carried out by demulsification-coagulation-purification process.After the treatment,the suspended solid content was 19.2mg/ L(unfiltered),the oil content was 0,and the corrosion rate was less than 0.076mm/a,the calcium loss rate was less than 3%,the TGB and IB was between 0 and 25 /m L,and the number of SRB was between 0 and 9 /m L in the treated fracturing flowback fluid,which reached the standard of “SY-T 5329-2012 Recommended Index for the Injection Water Quality for Clastic Reservoir and its Analyzing Method”. |
PDF Full Text Request