摘要
煤孔隙对煤层气赋存及运移具有关键控制作用,为了探究长平井田3号煤孔隙特征,为煤层气开发提供理论支撑,采用低温液氮吸附法对煤孔隙特征进行了研究。结果表明:受煤自身属性,煤岩组分、煤中矿物质含量、构造应力、煤变质、煤体破坏程度等地质要素的影响,煤孔隙形态复杂多样,样品间的孔径、孔比表面积及孔容存在显著分异。在众多影响要素中,煤变质作用对煤孔隙特征参数比表面积和孔容影响更为显著,煤体结构影响次之,煤变质程度升高,煤的孔比表面积随之增大,孔容减少。煤的孔比表面积和孔容总体随煤体破坏强度增加而呈增大趋势;煤变质煤中孔隙主要为墨水瓶孔、两端开口的狭缝、一端开口圆筒形孔及平板形孔圆筒孔;孔隙基本为介孔,微孔和大孔不甚发育,煤中开放型孔(有效孔)发育一般,煤孔比表面积和孔容相对偏低,不利于煤层气储集和高效渗流产出。
Coal pores have a key control effect on the occurrence and migration of coalbed methane.In order to explore the pore characteristics of No.3 coal in the Changping Minefield and provide theoretical support for the development of coalbed methane,the low-temperature liquid nitrogen adsorption method was used to study the pore characteristics of coal.The results showed that the pore morphology of coal was complex and diverse,and the pore diameter,specific surface area and pore volume of coal samples were significantly different due to the coupling effects of geological factors such as coal properties,coal rock components,mineral content in coal,tectonic stress,coal metamorphism,coal body damage degree and other geological factors.Among many factors,coal metamorphism had the most significant influence on the specific surface area and pore volume of coal pore characteristic parameters,followed by coal structure.With the increase of coal metamorphism degree,the pore specific surface area of coal increased,while the pore volume decreases.The pore specific surface area and pore volume of coal generally increase with the increase of coal failure strength.The pores in metamorphic coal are mainly ink-bottle hole,slit at both ends,cylindrical hole and flat hole at one end.The pores are mainly mesoporous,and the micropores and macropores are not well developed.The open pores(effective pores)in the coal are generally developed,and the specific surface area and pore volume of the coal pores are relatively low,which is not conducive to the reservoir of coalbed methane and the efficient seepage production.
作者
李瑶
LI Yao(Shanxi Lanyan Coalbed Methane Engineering Research Co., Ltd.,Jincheng 048012,China)
出处
《煤》
2021年第7期1-5,12,共6页
Coal
基金
国家科技重大专项(2016ZX05067)
山西省科技重大专项(20191102001)。
关键词
长平井田
3号煤层
低温液氮吸附法
煤孔隙特征
Changping Minefield
No.3 coal seam
low temperature liquid nitrogen adsorption method
pore characteristics of coal
