Polymer fracturing fluid gel after fracturing operation, residue remains in the fracture and side of fracture with causing reservoir damage, the decreased polymer concentration can reduce the damage, but will reduce viscoelastic behavior of the fracturing fluid gel as a result of proppant settlement problems. Therefore, to research on fracturing fluid of low concentration polymer with carrying sand has practical significance. We have synthesized thickening agent of fracturing fluid of low concentration polymer through chemical method, optimized cross-linking agent and gel breaker with experimental method, and evaluated general technical performance of the fracturing fluid of low concentration with resisted temperature and shearing and rheological property. The experimental results show that fracturing fluid of low concentration polymer of 0.24% can still meet the requirements of fracturing with carrying-sand, 50°C-120°C of reservoir temperature conditions of high temperature and shearing performance, and residue content of the gel broken is greatly reduced, less the reservoir damage, core permeability and damage rate of less than 18%, which is low damage fracturing fluid with environmental protection. Field application in 47wells show that the single well is average well fluid of 184m3, average gravel input of 33.3m3, average sand ratio of 28.7%, average maximum pump pressure of 36.6MPa, operation success ratio and technology effective rate of more than 90%.The application result indicates that the fracturing effect is 2.5 times that of guar gum fracturing fluid, and can effectively reduce the integrated water content of reservoir. Fracturing fluid of low concentration polymer with low damage characteristics is beneficial to reservoir protection, and provides reference for low damage fracturing of other types of reservoir.

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