Experimental Study on Solid Stick Additives for Water Injection into Coal Seams

Adding surfactant can significantly improve the wetting effect of water injection into coal seams. The solid stick additives for water injection into coal seams were prepared based on saponification reaction in 1aboratory, and the solubility of these additives were detected. The major componets of additives are anionic surfactant, and a small amount of nonionic surfactant. The result shows that the prepared additives could decrease significantly the surface tension of water inside in shorter time. Under hydrostatic water and atmospheric conditions, the surface tension of additives (formula 2) solution can be reduced to 24.56 mN/m after 10 h. Under dynamic water and high pressure conditions, the surface tension can be reduced to about 25 mN/m at least in 2 h by the rational control of water injection pressure and water flow.