The Sulige tight gas reservoir is characterized by poor physical properties, tiny pore throats, low fracturing coefficients, high contents of clay minerals and high sensitivity to damages induced by external fluids. To minimize the damages of reservoir induced by fracturing fluids and thereby enhance the well performance, researches were performed on low damage fracturing fluids. By adopting the cellulose modification technology and special crosslinker, a residue-free cellulose fracturing fluid system was developed. This system involves fewer kinds of additives. It can realize crosslinking under acidic conditions without addition of clay stabilizer, and enables the gelatinizer to dissolve fast. Lab tests show that the cellulose thickener may swell and reach 97.2% of its maximum viscosity within 2 min. When shearing at 90°C and 170 s-1 for 90 min, the apparent viscosity of fracturing fluid is 390.2 mPa·s, the surface tension and interface tension of gel-breaking fluid are 24.35 mN/m and 1.05 mN/m respectively, the residue content of fracturing fluid is zero, and the core damage rate is 12.3%. Thus, this cellulose fracturing fluid demonstrates rapid viscosity enhancing ability, high temperature-resistance, high shear resistance, fast and thorough gel breaking and residue-free., making it more suitable for tight gas reservoir. The new system can be prepared easily and conveniently on site. It was applied in 5 wells in East-2 Area of the Sulige Gasfield, with success rate of 100% and with open-flow capacity of 9.5×104 m3/d in production test. Compared with neighboring wells with identical geologic conditions, the average post-fracturing flow-back time for broken glue was reduced by 55%, and the average open-flow capacity was enhanced by 180%. With outstanding performance in productivity enhancement, the new system is worthy of extensive promotion.

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