淮北矿区岩浆岩侵入对煤储层微孔隙特征的影响

摘要

The measured vitrinite reflectance（Ro）,low-temperature nitrogen gas adsorption,carbon dioxide adsorption and scanning electron microscopy（SEM） analyses were carried out with 23 fresh samples from Wolonghu and Haizi Mine of Huaibei coalfield at various distances from two sills was done.Comparative analysis of the relation between micropores（micropore surface area,micropore volume and average micropore diameter） and the BET surface area of coal seams and the distance from sills was done.The results show that Ro levels of the Wolonghu coal increases from 2.74% to 5.03% near the sill.Approaching the intrusion,Ro levels of the Haizi coal increases from 2.30% to 2.78%.It is concluded that the contact-metamorphism of the sill in the Wolonghu Mine decreases the micropores and the BET surface area of coal（0~5 m from sill）,while the thermal evolution of sill increases it of coal（5~60 m from sill）,and the thermal evolution of sill in the Haizi Mine increases it of coal（60~160 m from sill）.The scanning electron microscopy found massive devolatilization vacuoles of coal in the thermal evolution zone.%以淮北矿区卧龙湖和海孜煤矿与岩床不同距离的23个煤样为研究对象,采用镜质组反射率（Ro）测定、低温液氮吸附试验、CO2吸附法测微孔（〈2 nm）和扫描电镜的方法,对比分析了煤样的微孔（D-A微孔孔容、D-R微孔比表面积和微孔直径）、BET比表面积和与岩浆岩距离的关系。结果表明：靠近岩床,卧龙湖煤样Ro由2.74%增加到5.03%,海孜煤样Ro由2.30%增大到2.78%。卧龙湖岩床的接触变质作用使距离岩床0～5 m煤的微孔和BET比表面积变小,热演化作用增加了距离岩床5～60 m煤的微孔和BET比表面积。海孜巨厚岩床的热演化作用增加了距离岩床60～160 m煤的微孔和BET比表面积。扫描电镜发现热演化区煤样出现大量和岩浆活动有关的热解气孔。