库拜煤田铁东矿区煤层气成藏条件分析

Analysis of Coalbed Methane Accumulation Conditions in Tiedong Mining Area of Kubai Coalfield

本文通过系统分析塔里木盆地北缘库拜煤田铁东矿区的煤岩煤质特征、孔渗特征及含气性,在此基础上从火烧区、水动力条件、水化学特征等方面阐述了影响研究区煤层气成藏的特殊因素。研究结果表明:研究区主力煤层发育为长焰煤-气煤;宏观煤岩类型以亮煤为主,含少量暗煤;显微煤岩组分中,镜质组含量最高、惰质组含量次之、壳质组含量最少;属于低水分、特低-低灰、中-中高挥发分煤;中孔所占比例较大,大孔次之,过渡孔和微孔所占比例很小,渗透率较大,甲烷吸附空间不足但有利于煤层气的渗流。

This paper systematically analyzes the characteristics of coal petrography and coal quality,the porosity-permeability and the gas-bearing properties in Tiedong Mining Area of Kubai Coalfield in the northern margin of Tarim Basin.On this basis,the special factors affecting the formation of coalbed methane in the studied area are explained from the aspects of burning area,hydrodynamic conditions and hydrochemistry characteristic.The research results show that long flame coal-gas coal is developed in the main coal seams of the studied area.The macro coal rock type is mainly clarain with a small amount of durain.Among the microscopic coal rock components,the vitrinite content is the highest,the inertite content is the second,and the content of exinite is the least.It belongs to low moisture,extra-low-low ash,and medium-medium to high volatile coal.The proportion of mesopores is larger,followed by macropores,and the proportion of transition pores and micropores is small.The permeability is relatively high,and the methane adsorption space is insufficient but conducive to the seepage of coalbed methane.