Abstract To explore the influence of surfactant concentration on the pore structure and permeability of coal samples during the chemical enhancement of coalbed methane production. different kinds and different concentrations of surfactants were added to the chemical solution. and the coal samples were soaked. Methods such as low-field nuclear magnetic resonance testing (NMR). https://ashleyshomestores.shop/product-category/wall-art-set-of-2/