应力约束下储存CO_2煤层膨胀变形特性试验研究  

Experiment on swelling strain of confined coal mass with CO_2 sequestration

作　　者：张倍宁[1,2] 梁卫国[1,2] 韩俊杰[1,2] 李治刚[1] 

机构地区：[1]太原理工大学矿业工程学院,山西太原030024 [2]太原理工大学原位改性采矿教育部重点实验室,山西太原030024

出　　处：《煤炭学报》2016年第2期324-331,共8页Journal of China Coal Society

基　　金：国家杰出青年基金资助项目(51225404);"三晋学者"支持计划资助项目(2013)

摘　　要：利用自主研发的MCQ-Ⅱ型煤层瓦斯驱替试验装置,对原煤大尺寸(100 mm×100 mm×200 mm)试件,进行了恒定温压(25℃,31 MPa)条件下CO_2在贫煤、贫瘦煤和弱黏煤3种煤阶煤中的注入储存试验,对CO_2注入储存过程中煤体膨胀变形特性进行了测量分析;并对小尺寸(6 mm×6 mm×6 mm)原煤试件通过CT扫描,研究了3种煤样的微观结构特征。主要结果为:对最小观测尺度为4.5μm的CT重建图像,通过统计分析,发现贫煤孔隙率(4.67%)小于贫瘦煤孔隙率(5.39%)小于弱黏煤孔隙率(12.10%);在31 MPa体积应力约束条件下,持续12 h的CO_2注入过程中,煤体膨胀变形受孔隙压力与CO_2吸附变形的共同作用,且体积膨胀百分比与CO_2注入储存量呈线性关系;在注入储存相同量气态CO_2条件下,贫煤体积膨胀应变大于弱黏煤大于贫瘦煤;由于煤体层理性结构特征,弹性模量在垂直与平行层理2个方向上的差异性,煤体在垂直层理方向膨胀应变大于平行层理方向应变,且2个方向膨胀应变均与CO_2储存量呈线性关系。In order to investigate the coal volumetric swelling during CO2 storage,the self-developed MCQ-ⅡCO2-ECBM experimental equipment was used to perform coal deformation through injecting CO2 to meager coal,meagerlean coal and weakly caking coal samples（100 mm × 100 mm × 200 mm） with constant injection pressure under31 MPa bulk stress at 25 ℃. At the same time, the micro-pores were investigated with nine small coal samples（6 mm×6 mm×6 mm） through a micro-CT system. The results show that：At minimum 4. 5 μm observation of CT sec-tion structure,the meager coal porosity（4. 67%） is less than that of meager lean coal（5. 39%） and weakly cakingcoal（12. 10%）;During 12 hours of CO2 injection,coal volumetric strain is influenced by pore pressure and CO2ad-sorption swelling,which is linearly proportional to the amount of gaseousness CO2 storage under 31 MPa confinementpressure;With the same CO2 storage,the volumetric swelling strain of the meager coal is more than that of the weaklycaking coal and meager lean coal;Due to the anisotropy of modulus of elasticity,the radial strain increases faster thanthe axial strain and both of them are linearly proportional to the amount of gaseousness CO2 storage.

关 键 词：CO2煤层储存 煤体膨胀变形 变形各向异性 孔隙率 

分 类 号：P618.11[天文地球—矿床学]