Abstract:For hydraulic fracturing in low-pressure strong hydrophilic tight gas reservoirs, due to the invasion of a large number of outside fluids, the production of gas reservoirs is low, and fracturing is not effective. At present, the most extensive, simple and economical are the addition of anti-water blocking agent to prevent water blockage. A large number of anti-water blocking agents on the market are not well applied, and the reason is that anti-water blocking agents need to be added to the fracturing fluid system (or in the pre- fracturing fluid). Therefore, its screening and application need to evaluate the impact of its carrier and use environment on its performance, and to make sure the anti-water blocking agent performs its proper function. Three different types of surfactants, fluorocarbon anion, fluorocarbon nonionic and self-developed nano-FC-ST, were studied to investigate the effects of different factors on their performance. The results showed that the viscosity of the fracturing fluid was greater than 4mPa.s, it would affect the dissolution diffusion of the surfactant, reduce the activity, enhance the hydrophilicity, and pay attention to the degradation of low viscosity fracturing fluid; the nano-FC-ST could maintain stable performance at 120°C and APS of 0.5g/L, meet the temperature requirements of low-pressure strong hydrophilic tight gas reservoirs, and it could tolerate mineralization of water quality up to 1×105mg/L, the alkali resistance ranged from pH ≤11. Nano-FC-ST in the slick water fracturing fluid could significantly reduce the capillary force, reduce spontaneous imbibition of the water, reduce adsorption in the near well zone, and it had a recovery rate of more than 50% permeability, compared with conventional anti-water blocking agent, drainage aid, the performance was less affected by the carrier and the environment, the performance of the water blockage prevention is remarkable.