Treatment of high viscosity fracturing flowback by electrolytic brine-catalyzed oxidation

Abstract With the increasing application of hydraulic fracturing technology in exploration of tight oil and shale gas, the treatment of accompanying fracturing flowback fluids has become more urgent. Fe/Ni catalyst was successfully applied in the treatment of the flowback fluid for the first time in this paper. The effects of different oxidants and catalysts on the treatment of fracturing flowback were investigated. Electrolytic brine was an optimal oxidation gel breaker and molecular sieve loaded with Fe/Ni as catalyst for the treatment of fracturing flowback. Fe/Ni catalyst was characterized by SEM, EDS analysis, TEM and XRD, and the catalytic effect of the Fe/Ni proportion was explored. Fracturing flowback that dealt with catalytic oxidation was mixed with polyaluminum chloride (PAC) and polyacrylamide (PAM) for flocculation and sedimentation, through a filter, and was continuously treated for 20 days to simulate on-site operation. Finally, the suspended solids (SS) content of the fracturing flowback was steadily less than 15 mg/L, which meets the reinjection standard of fracturing flowback (SY/T 5329-2012 (China)). Hence, electrolytic brine-catalyzed oxidation treatment of high viscosity fracturing flowback possess broad application prospects.