Study on Performance of Fracturing Fluid Based on Surfactant Releasing Water Locking Effect

In order to solve the problem of water locking effect in the process of hydraulic fracturing in coal seam, we analyzed the influencing factors of water locking effect and selected the method of adding surfactant to the fracturing fluid to solve the water locking effect. The results show that the selected seven kinds of surfactants can improve the wetting property of the coal, and the higher the concentration of the surfactant, the smaller the contact angle, the better the wetting property and the more the surface tension reduced, until it tends to be flat; the adhesive work of seven kinds of surfactants is less than that of pure water; the capillary force between the fracturing fluid and the pore wall of the coal body is calculated based on Laplace formula, and by comparing the magnitude of σcosθ, the anionic surfactant SDBS is the best choice for reducing the capillary force.