含瓦斯煤渗透率各向异性研究

Experimental study on anisotropic permeability rule of coal bearing methane

为研究含瓦斯煤各向异性渗流特征,以原煤煤样为研究对象,以含瓦斯煤三轴渗流实验系统为实验平台,开展了含瓦斯煤的各向异性渗流规律的研究,确定了含瓦斯煤各向异性渗透率主值及其方位的计算方法,定义了含瓦斯煤渗透率各向异性率,重点分析了含瓦斯煤渗透率各向异性动态变化规律和瓦斯优势流动方向的转变现象。研究结果表明:煤体瓦斯流动具有非常明显的各向异性特征,本文所提出的含瓦斯煤各向异性渗透率计算方法简单有效;含瓦斯煤具有较强的应力敏感性,其渗透率与有效应力之间符合负指数函数变化规律;含瓦斯煤渗透率的各向异性随有效应力的变化表现出了明显的动态变化发展规律,优势流动方向存在转变现象。

In order to study the characteristics of anisotropic seepage of coal bearing methane,the raw coal samples were taken. Based on the tri-axial seepage experimental system the study of anisotropic seepage rule of coal bearing methane was carried out. The calculation method of the principal value and its azimuth of anisotropic permeability of coal bearing methane were determined. Permeability anisotropic ratio of coal bearing methane was defined. Permeabili ty anisotropic dynamic variation rule and the phenomenon of the change of the dominant flow direction of coal bearing methane were analyzed emphatically. The results show that the flow of methane of coal has the very obvious character istics of anisotropy,the calculation method of anisotropy permeability of coal bearing methane proposed in this paper is simple and effective. The coal bearing methane has strong stress sensitivity,and the variation rule between permeability of methane of coal and effective stress is according with negative exponential function. The change of the permeability anisotropy of methane of coal with effective stress shows an obvious dynamic change law of development,the dominant flow direction of methane of coal exists the phenomenon of change.