Chemical regulation of coal microstructure and study of water injection displacement gas law

In order to reveal the effect of changes in coal microstructure on gas desorption, this study selected coal samples from the Eighth Mine in Pingdingshan, Henan Province as the research object, and used two surfactants, 1-Butyl-3-methylimidazolium tetrafluoroborate and Sodium dodecyl sulfate, to soak the coal samples. The coal samples were investigated by low temperature liquid nitrogen adsorption, infrared spectroscopy, X-ray diffraction, the measurement experiment of adsorption constant a, contact angle measurement, and gas displacement and desorption experiment. The findings indicate that surfactants can dramatically alter the pore properties, molecular groups, and microcrystalline structure of coal. The specific surface area of the coal sample micropores decreases and the average pore diameter increases, so that the pore and fracture network is more smooth. The chemical functional groups of the coal samples change, the average chain length and the fat ratio decrease, and the oxygen enrichment degree increa