Development of resource treatment technology for fracturing backflow fluids of tight sandstone

Fracturing is an important means to realize the development value of tight sandstone unconventional reservoirs, which consumes serious water resources and generates high viscosity of backflow fluid with petroleum and suspended matter pollutants. Therefore, it is of great significance to recycle fracturing fluid from tight sandstone with low-carbon and environmental protection. In this study, the fracturing fluid of tight sandstone in a block of a certain oilfield was collected as the research object, and a comprehensive water quality analysis was carried out. The combined process technology for resource treatment of fracturing flowback fluid in tight sandstone were formed by studying on the influence factors of oxidation gel breaking, flocculation sedimentation, ion removal, filtration and process optimization. After treatment, the mass concentration of iron ion in fracturing flowback fluid was less than 5 mg/L, the mass concentration of suspended matter was less than 10 mg/L, and the mass concentration of oil was less than 5 mg/L, which could meet the water quality requirements of fluid distribution and reuse, and avoid the environmental pollution risk of flowback fluid effectively, while the consumption level of water resources in fracturing construction also was greatly reduced. This paper will have positive significance for the resource treatment technology and development of tight sandstone fracturing fluid.