Research and Field Application of Salt-Tolerant On-Line Prepared Fracturing Fluid System for Mixed Sedimentary Low-Saturation Gas Reservoirs in Qaidam Basin

The mixed sedimentary low-saturation gas reservoirs in the western Qaidam Basin have complex geological conditions. The reservoirs are tight, and hydraulic fracturing is required to obtain gas flow. With a high clay content and a high risk of reservoir damage, strict requirements are imposed on the performance of fracturing fluid, and traditional fracturing fluids can hardly meet the demands. By analyzing the current development status of fracturing fluid technology and combining the characteristics of the reservoirs with the results of anti-swelling experiments, research on the salt-tolerant on-line prepared fracturing fluid technology was carried out. This paper elaborates on the research and development process and performance evaluation of the 1% KCl brine and flowback fluid fracturing fluid systems. Field tests show that the salt-tolerant on-line prepared fracturing fluid system has stable application performance and remarkable effects in the reservoir stimulation of the mixed sedimentary low-saturation gas reservoirs in the western Qaidam Basin. It provides crucial technical support for reservoir stimulation in this area and also serves as a reference for the optimization of fracturing fluid systems and the utilization of flowback fluids in other similar reservoirs.