Daniudi Gas Field is a typical tight sandstone reservoir. It has low nature production capacity without hydraulic fracturing. In the procedure of hydraulic fracturing, fracturing fluid enters the reservoir inevitably, resulting in a series of reservoir damages and affecting the fracturing effect. According to the engineering geological characteristics of low porosity, low permeability and low pressure, rich in clay minerals, high capillary force and local ultra-low water saturation in work area, and through a lot of lab experiments on fracturing fluid evaluation, this paper makes a deep analysis of the influences of liquid phase trapping, solid invasion, clay minerals migration, sensitivity damage, the fracturing fluid and reservoir compatibility on reservoir damage. The results show that liquid phase trapping and solid phase damage are the main reasons of reservoir damage. Capillary imbibition, clay mineral migration, alkali sensitivity and solid phase deposition exacerbate liquid phase residence and pore throat blocking, reducing the effective seepage of pore throat and decreasing the reservoir permeability. The poorer the reservoir physical property is, the stronger the heterogeneity is. The more serious the liquid phase residence and the reservoir damage are, the worser the backflow effect of fracturing fluid is.
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