基于表面活性剂解除水锁效应的压裂液性能研究
Study on Performance of Fracturing Fluid Based on Surfactant Releasing Water Locking Effect
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摘要: 为解决煤层水力压裂过程中产生的水锁效应问题,对水锁效应产生的影响因素进行了分析,选择向压裂液中添加表面活性剂的方法来解除水锁效应。研究结果表明:所选用的7种表面活性剂都可以提高煤体的润湿性能,且表面活性剂的浓度越高,其接触角θ越小,润湿性能越好,表面张力σ降低的越多,直到趋于平缓;7种表面活性剂的黏附功都小于纯水的;根据Laplace公式计算压裂液和煤体孔隙壁之间的毛细管力,通过比较σcosθ的数值大小,得到阴离子表面活性剂SDBS是降低毛细管力的最佳选择。Abstract: 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.