贵州金佳矿区煤储层孔隙结构及等温吸附特征

Pore Structure and Isothermal Adsorption Characteristics of Coal Reservoir in Jinjia Mining Area,Guizhou Province

采用扫描电镜、压汞试验、等温吸附实验分析贵州金佳矿区8个主要煤层孔隙发育特征。煤储层发育较多的原生孔、气孔及张性裂隙,次生孔隙主要为粒间孔,矿物溶蚀孔、矿物铸模孔相对较少;压汞试验表明,3#煤层开放孔较多,压汞曲线为Ⅱ型,孔隙连通性较好;1#、7#煤层以微小孔为主,压汞曲线为Ⅰ型,孔隙连通性中等;其余煤层压汞曲线为Ⅲ型,孔隙连通性差;煤储层孔隙度、孔容、比表面积与变质程度呈正相关;甲烷等温吸附实验显示3#、24#煤甲烷吸附速率快,吸附能力最强;矿区煤储层孔隙结构对甲烷吸附性的影响有限;对比分析矿区3#煤层有利于煤层气的开发。

The pore development characteristics of 8 main coal seams in Jinjia mining area of Guizhou Province were analyzed by means of SEM,mercury injection test and isothermal adsorption test. There are more primary pores,pores and tensile fractures in coal reservoir,secondary pores are mainly intergranular pores,and mineral dissolution pores and mineral mold pores are relatively less;mercury injection test shows that there are more open pores in No.3 coal seam,mercury injection curve is type Ⅱ,and pore connectivity is good;No.1 and No.7 coal seams are mainly micro pores,mercury injection curve is type Ⅰ,and pore connectivity is medium;mercury injection curve of other coal seams is Ⅲ The results show that the methane adsorption rate of No.3 and No. 24 coal is the fastest,and the adsorption capacity is the strongest;the influence of pore structure of coal reservoir on methane adsorption is limited;comparative analysis of coal seam No.3 is conducive to the development of coalbed methane.