低渗透煤的孔隙结构特征及其瓦斯吸附特性

Pore Structure and Gas Adsorption Characteristics of Coal with Low Permeability

采用压汞实验和高压等温吸附实验分析不同变质程度煤的孔隙结构特征及瓦斯吸附能力,并结合煤样工业分析数据,进一步探讨孔隙结构特征对煤层瓦斯渗透性影响。研究表明:2种煤样的压汞孔隙率随煤级的升高呈现出从高到低的变化趋势;松河3号煤样的孔径分布呈现出微小孔径的单峰特点,而林华9号煤样的孔径分布呈现出小孔径和中、大孔径的双峰特点;高压等温吸附实验测的松河3号煤的瓦斯吸附能力要强于林华9号煤。结论认为:煤的孔隙特征、孔隙率和瓦斯吸附能力均受煤变质程度的影响,且在低变质煤特征突出。

In this paper, mercury intrusion experiment and high pressure isotherm adsorption experiment were used to analyze the pore structure characteristics and gas adsorption capacity of different metamorphic degrees of coal. Combined with industrial analysis data of coal samples, further investigate the effect of pore structure characteristics on coal seam gas permeability is carried out. The research shows that: the mercury porosities of the two kinds of coal samples show a trend of changing from high to low with the increase of coal ranks;the pore size distribution of Songhe No. 3 coal sample shows the single peak characteristic of the tiny pore size;the pore size distribution of Linhua No.9 coal sample shows the double peak scharacteristics of small pore diameter and medium and large pore diameters;the gas adsorption capacity of Songhe No. 3 coal measured by high pressure isotherm adsorption experiment is stronger than that of Linhua No.9 coal. The conclusion is that the pore characteristics, porosity and gas adsorption capacity of coal are affected by the degree of coal metamorphism, and the features of low metamorphic coal are outstanding.