Shanxi Xishan Coal Electricity (Group) Co., Ltd. Malan Mine

煤层气扩散特征研究对提高煤层气产量和减少矿井瓦斯灾害具有重要意义。基于国内外学者在煤层气扩散领域取得的成果,从煤层气扩散模型、扩散实验和扩散控制因素等3方面进行系统研究。结果表明:基于Fick定律的单孔扩散模型不能描述吸附/解吸扩散全过程,双孔扩散模型、多孔扩散模型和基于时间变化的动态扩散模型能更好解释扩散特征;测压法和质量法用来获取吸附扩散系数,体积法用来获取解吸扩散系数,选择合适的扩散模型拟合实验数据是获取扩散系数的关键;煤层气扩散特征主要受控于煤阶、孔隙结构、煤岩水分、温度、压力和粒径。探寻扩散系数随时间变化规律,定量不同孔径扩散模型,明确扩散渗流联合机制,是该研究领域的发展趋势。

The study of coalbed methane diffusion characteristics is of great significance for improving coalbed methane yield and reducing mine gas disasters. Based on the achievements of domestic and foreign scholars in the field of coalbed methane diffusion, a systematic study is conducted from three aspects, such as coalbed methane diffusion models, diffusion experiments, and diffusion control factors, etc. The results show that the single hole diffusion model based on Fick's law cannot describe the entire process of adsorption/desorption diffusion, while the dual hole diffusion model, porous diffusion model, and dynamic diffusion model based on time variation can better explain the diffusion characteristics; the manometry method and mass method are used to obtain the adsorption diffusion coefficient, while the volume method is used to obtain the desorption diffusion coefficien, choosing a suitable diffusion model to fit experimental data is the key to obtaining the diffusion coefficient; the diffusion characteristics of coalbed methane are mainly controlled by coal rank, pore structure, coal rock moisture, temperature, pressure, and particle size. Exploring the law of diffusion coefficient changing with time, quantifying diffusion models with different hole sizes, and clarifying the joint mechanism of diffusion and seepage flow are the development trends in this research field.