Study on Degradable Fiber Fracturing Fluid and Its Application in Sulige Gas Field

To improve the placement efficiency of proppants in the Sulige gas field, prevent sand production and backflow of the proppants, a fiber used in fracturing fluids was surface modified, and the size distribution and concentration of the fiber particles were optimized. Laboratory experiments on several parameters related to fracturing job, such as the degradability, dispersibility, damage to core, sand suspension performance of fiber, high temperature resistance and gel breaking property of fracturing fluid, were performed. It was found that fiber particles with diameter of 10 μm and length of 12 mm have good dispersibility in a fracturing fluid at concentration of 0.15%, and 80% of the fiber particles can be degraded after 120 h of dissolution in the fracturing fluid. Rate of core damage caused by the degraded fibers is less than 5%. The fiber has good viscosifying performance in the fracturing fluid, the viscosity of the fracturing fluid after shearing at 170 s^-1 and 110 ℃ for 120 min was still higher than 120 mPa·s. The fiber, by the bridging action between the particles, forms a network structure, thereby bonding the proppant particles within the fracturing fluid and reducing the settling velocity of the proppant. Field experiment found no sand production and backflow of proppant, and the open flow capacity of the well fractured with the GT-1 fracturing fluid is 108.61 × 10⁴ m³/d, indicating that the fracturing job has met the expected goal.