煤层瓦斯运移过程中扩散对渗流的影响机制反分析研究

The gas migration in coal by adsorption, desorption, diffusion and seepage, interaction of different migration modes affects the gas drainage rate. The project study the mutual feedback mechanism on gas migration in coalseam which influence the drainage rate significantly with the theory combined experiment method. By Identify the unknown coefficient functions and unknown source term of variable coefficient nonhomogeneous parabolic partial differential equation, solve the permeability coefficient affected by the deformation and stress and determine the diffusion - seepage mutual feedback mechanism of gas for the first time. Design three axis gas migration test of the coal samples , improve the experimental equipment of gas pressure observation system , abserve the gas pressure of the fixed position in the sample, identify the unknown diffusion source of control equation of gas migration by using basic solution with Tikhonov regularization method, reveal the gas diffusion - seepage mutual feedback mechanism in the coal, establish the fluid-structure interaction model of gas migration in coal , numerical simulate the coal seam gas migration rule, and compared to the coal seam gas drainage data to validate the mechanism. The research of gas migration rule based on diffusion – seepage mutual feedback mechanism enrich the theory of gas migration of coal seam, provide theoretical basis for increase the rate of coal seam gas extraction and realize the safe and high-efficiency extraction of coal and gas.

煤层瓦斯在煤体中吸附、解吸、扩散和渗流运移模式间的相互作用影响煤层瓦斯的抽采率。项目采用理论和实验相结合的方法，对影响抽采率显著的煤层瓦斯扩散对渗流运移模式的影响机制展开研究。首次提出利用变系数非齐次抛物型微分方程未知系数函数和源汇项函数识别的反分析方法，求解渗透系数受应力变形耦合作用的瓦斯渗流规律，确定瓦斯运移的扩散对渗流影响机制。设计原煤试件中瓦斯的三轴运移实验，改进实验设备的瓦斯压力观测系统，测试试件轴向端点及中间固定点的瓦斯压力变化，采用基本解结合Tikhonov正则化方法，识别瓦斯运移控制方程中的未知扩散源，揭示瓦斯在煤体中的扩散对渗流影响机制，进而建立瓦斯在煤体中运移的流固耦合模型，数值模拟本煤层瓦斯运移规律，并以本煤层瓦斯抽放数据进行对比验证。基于扩散对渗流影响机制的瓦斯运移规律研究，丰富了煤层瓦斯运移理论，为提高煤层瓦斯抽采率，实现煤与瓦斯的安全、高效共采提供理论基础。

煤层瓦斯在煤体中吸附、解吸、扩散和渗流运移模式间的相互作用影响煤层瓦斯的抽采率。项目采用理论和实验相结合的方法，研究了煤层瓦斯扩散对渗流运移模式的影响机制。利用抛物型微分方程未知系数函数和源汇项函数识别的反分析方法，求解了渗透系数受应力变形耦合作用的瓦斯渗流规律，确定了瓦斯运移的扩散对渗流影响机制。设计了原煤试件中瓦斯的三轴运移实验，改进了实验设备的瓦斯压力观测系统，测试了试件轴向端点及中间固定点的瓦斯压力变化，采用基本解结合Tikhonov正则化方法，识别了瓦斯运移控制方程中的未知扩散源，揭示了瓦斯在煤体中的扩散对渗流影响机制，进而建立了瓦斯在煤体中运移的流固耦合模型，数值模拟了本煤层瓦斯运移规律，并以本煤层瓦斯抽放数据进行了对比验证。基于扩散对渗流影响机制的瓦斯运移规律研究，丰富了煤层瓦斯运移理论，为提高煤层瓦斯抽采率，实现煤与瓦斯的安全、高效共采提供理论基础。