煤层注水被广泛用于煤层瓦斯治理，其治理瓦斯的效果关键在于水分对含瓦斯煤体的润湿效果，然而高瓦斯煤层中瓦斯严重干扰着水分对煤体的润湿。为弄清瓦斯氛围下水分对煤体的润湿特性，采用自研的瓦斯氛围下煤−水接触角测试装备及自开发的瓦斯氛围下水的表面张力测试软件，研究了瓦斯氛围下煤−水界面润湿参数，阐释了瓦斯氛围下煤−水界面的润湿特性，并揭示了其影响机制。研究结果表明：瓦斯氛围下随着瓦斯压力的增加，水的表面张力、煤的表面能及黏附功逐渐减小，煤−水接触角及煤−水界面能逐渐增加，水对煤的润湿效果变差；基于煤的工业分析、元素分析及微光谱图分析，建立了无烟煤的分子结构模型，分子式为C₉₉H₅₄N₂O₃S，煤分子模型的桥碳比为0.61，其与¹³C-NMR谱图的桥碳比一致；瓦斯氛围下煤水微观润湿体系中，煤水交界面以下，水分子的相对浓度随着瓦斯压力的增大而减小；煤水交界面以上，瓦斯压力越大，水分子相对浓度峰值越大；瓦斯氛围下煤水微观润湿体系中，随着瓦斯压力的增加，水分子的吸附程度减弱，煤中瓦斯被置换的程度减小，甲烷分子的扩散系数减小，水分子分散程度增加，聚集程度减弱，水分子的扩散系数增加。

Coal seam water injection is widely used for coal seam gas control, and the key to its effectiveness in controlling gas lies in the wetting effect of water on coal body. However, the gas in coal seriously interferes with the wetting effect of water on coal. This paper uses a self-developed coal and water contact angle testing equipment under gas atmosphere and a self-developed water’s surface tension testing software under gas atmosphere to study the wetting parameters of coal and water interface under gas atmosphere, elucidating the wetting characteristics of coal and water interface under gas atmosphere and revealing its influencing mechanism. The results show that the surface tension of water, surface energy of coal, and adhesion work gradually decrease with the increase of gas pressure in a gas atmosphere. However, the coal and water contact angle and coal and water interface energy gradually increase with the increase of gas pressure, which implies a decrease in the wetting effect of water on coal. A molecular structure model of anthracite coal has been established based on the industrial analysis, elemental analysis, and micro spectral analysis of coal. The molecular formula of coal can be described by C₉₉H₅₄N₂O₃S. The bridge carbon ratio of the coal molecular model is 0.61, which is consistent with the bridge carbon ratio in the ¹³C-NMR spectrum. In the micro wetting system of coal water under gas atmosphere, with the increase of gas pressure, the adsorption degree of water molecules weakens, the degree of gas displacement in coal decreases, the diffusion coefficient of methane molecules decreases, the dispersion degree of water molecules increases, the aggregation degree of water molecules weakens, and the diffusion coefficient of water molecules increases. The research results lay a theoretical foundation for revealing the mechanism of wetting coal containing gas by coal seam water injection.