基于煤非均匀性的深部煤层瓦斯扩散机理与分形模型

On the basis of previous studies and the existing problems on gas diffusion, the research will be carried out based on many thiroeis. Firstly, the research samples will be selected in the deep coalbed. And the microstructure and composition changes of coal samples are to be resarched by conventional testing, particle size analysis, pore structure testing. The gas diffusion experiments on binary-component gas will be carried out with equilibrium water coal sample in the conditions of high temperature and pressure and three-phase medium. Secondly, the coal fracture dimension will be introduced to characterize its inhomogeneity of complex structure. Mathematical model of gas desorption and diffusion will be established based on the physical adsorption theory of inhomogeneous solid and diffusion theory of fractal medium. Lastly, the characteristic and mechanism of gas diffusion in deepcoalbed will be analyzed under the conditions of three-phase medium. Through these studies, the deep coal geological theory will be tried to make progress. And it is hoped that research results can provide a theoretical basis for a deep coal seam gas disaster prevention and deep coalbed methane resources exploration and development.

在借鉴前人已有研究成果的基础上，基于煤岩学、瓦斯（煤层气）地质学、力学、分形几何学、物理化学及界面化学、统计热动力学、物理模拟和数值模拟等学科理论，针对深部煤层瓦斯扩散机理及理论模型存在的问题，选择深部煤层煤样作为研究用样，综合采用常规测试、孔隙结构测试和形态观测分析等测试手段和方法，模拟深部煤层温度、压力及三相介质条件，开展瓦斯扩散实验，基于煤孔隙表面的非均匀特征，引入煤的综合分形维数，对煤非均匀性进行表征，基于分形介质气体扩散理论，建立基于煤非均匀性的深部煤层瓦斯扩散数学模型，在上述研究的基础上，分析深部煤层三相介质条件下瓦斯扩散特征以及控制机理。通过以上研究，力图在深部煤层地质理论方面有所进展，并期望研究成果能为深部煤层开采瓦斯灾害防治和深部煤层气资源勘探与开发提供理论依据。

按照本资助项目的《计划书》，经过本项目科研人员共同努力，完成了计划中所要求的研究工作，实现了预期的研究目标。本次研究选择代表性的矿区不同地质时期形成的不同类型煤样作为研究用样，模拟深部煤储层条件，开展了高温高压瓦斯扩散实验，耦合分析了温度、压力、煤级、微观结构以及岩石学组成等特征对瓦斯扩散的影响，探寻深部煤层瓦斯扩散的动态控制机理。定义并计算了煤的全孔径孔隙分形维数，对煤的非均匀性进行表征。建立了深部煤层瓦斯扩散数学模型，模型精度高，具有更普遍的理论意义。此项研究，对煤层气资源评价和预测、煤层气开发区块优选、井下瓦斯防治和抽采提供了有效方法，具有更普遍的理论意义和广阔的应用前景。