Optimization and evaluation of a high-temperature resistance fracturing fluid formula

The objective fracturing formation in Hui 25 area is characterized by great buried depth( about 5 000 m),high temperature( 150 ~ 160 ℃) and tight lithology. It has high requirement to the performance of the fracturing fluid. For this reason,a novel fracturing fluid with high temperature-resistance and low friction is developed with organic boron-zirconium compound crosslinking agent Gh-g and composite temperature stabilizer based on laboratory study,and the performance of the fracturing fluid is evaluated accordingly. The experimental results show that the fracturing fluid system has a good performance under high temperature and high shearing rate. Its viscosity can maintain 100 mPa·s or even more after shearing 90 min at 160 ℃ and 170 s- 1. Furthermore,the system exhibits the feature of delayed crosslinking. It takes 120 s to crosslink completely. Another property of the fluid system is its low friction and the friction reduction rate is 35% ~ 70%. Moreover,laboratory experiments show that the fluid system has low damage to formation,and the average permeability reduction rate of cores is 17. 92%. All these advantages ensure this fracturing fluid system to meet the requirements of the fracturing construction.