黄陇煤田转角勘查区煤的微观孔隙结构特征及其影响因素

煤的微观孔隙结构特征是煤储层特征的重要研究内容之一。选取黄陇侏罗纪煤田转角勘查区4个典型低阶煤样品为研究对象,以煤质特征研究为基础,进行压汞和液氮吸附实验,获取了不同测试方法的煤孔隙结构参数。根据两种测试方法的优缺点在孔径50nm处采用曲线拼接法进行联合,分析了全孔径段的比表面积和孔隙体积分布。结果显示:煤的比表面积主要分布在微孔、小孔和中孔三个区间,呈现“三峰”特征,表现为微孔>小孔>中孔>大孔的分布特征;孔隙体积主要分布在微孔、小孔和大孔。灰分含量和阶段孔径比表面积和孔隙体积具有较好的相关关系,但相关性强弱不同,总体显示和微孔、小孔及中孔呈正相关关系,而与大孔孔隙呈负相关关系,灰分含量与微孔、小孔的影响最大。显微组分中的镜质组和壳质组含量与大孔比表面积和孔隙体积呈正相关关系,与微孔、小孔呈负相关关系;惰质组含量与大孔孔隙比表面积和孔隙体积呈负相关关系,和微孔、小孔呈正相关关系。

Microscopic Pore Structure Sharacteristics Coal Microscopic Pore Geometry Features and Its Impact Factors in Zhuanjiao Exploration Area,Huanglong Coalfield

To know coal microscopic pore geometry features is an important part in coal reservoir features study.Taking four typical low ranked coal samples from the Zhuanjiao exploration area,Huanglong Jurassic coalfield as the subject investigated,on the basis of coal quality features study has carried out mercury intrusion and liquid nitrogen adsorption tests,acquired coal pore geometry parameters from different test methods.According to merits and demerits of the two test methods,at the pore diameter 50nm,through curve matching carried out assemblage,analyzed full pore size specific surface areas and pore volumes distribution.The result has shown that coal specific surface areas are mainly distributed in micropore,minipore and mesopore three intervals,present“triple peak”feature,and showing in micropore>minipore>mesopore>macropore feature;main distribution of pore volumes are in micropore,minipore and macropore.Ash content,staged specific surface area and pore volume have better correlativity,but with different intensities;as a whole,present positive correlativity with micropore,minipore and mesopore,while negative correlativity with macropore;impact from ash content on micropore and minipore is largest.Maceral vitrinite and exinite content has positive correlativity with macropore specific surface area and pore volume;negative correlativity with micropore and minipore;inertinite content has negative correlativity with macropore specific surface area and pore volume,while positive correlativity with micropore and minipore.