煤体结构全程演变过程中渗透特性试验研究及意义  

Experimental study on permeability characteristics in complete evolution process of coal structure and its significance

作　　者：郭红玉[1,2,3] 拜阳[2] 蔺海晓[2] 李广生[2] 苏现波[1,2,3] 

机构地区：[1]河南省瓦斯地质与瓦斯治理重点实验室--省部共建国家重点实验室培育基地 [2]河南理工大学能源科学与工程学院 [3]中原经济区煤层(页岩)气河南协同创新中心

出　　处：《煤炭学报》2014年第11期2263-2268,共6页Journal of China Coal Society

基　　金：国家自然科学基金资助项目(41472127;41472129);山西省煤层气联合研究基金资助项目(2013012004)

摘　　要：在引入地质强度指标(GSI)实现煤体结构定量表征的基础上,通过平行煤样在应力应变不同阶段的结构特征、声发射和渗透率等参数的观测和拼接,得到煤体结构全程演变过程中渗透特性变化趋势。结果表明:煤体结构(GSI)改善阶段,煤样由压密向弹性变形过渡,声发射强度由弱变强,孔裂隙逐渐闭合导致渗透率降低;煤体结构(GSI)脆性破坏阶段,煤样发生屈服和破裂,声发射强度逐渐增强,随着裂缝充分扩展,渗透率增加滞后并达到最大值;煤体结构(GSI)塑性降低阶段,先期形成裂隙的凹凸部分被剪切和磨蚀,连通性变差,煤样逐渐粉末化,声发射计数明显增加但强度较小,随着应变增加,应力曲线缓慢上翘,达到重新压实效果,渗透率急剧下降。Coal reservoir＇s permeability is closely related to its coal structure,their relationship is of significance to the method optimization of permeability increase for coal reservoirs with different structures. Based on the introduction of geological strength index（ GSI） to quantitatively characterize the coal structure,the corresponding parameters including coal structure,acoustic emission and permeability,etc were tested and analyzed. Subsequently the variation trends of permeability features with different coal structures in a complete evolution process were discovered. The results show that during the improvement phase of coal structure（ GSI）,the coal samples transit from compaction to elastic deformation; the acoustic emission strength turns from weak to strong and the permeability decreases due to the gradual closure of micro-fissures. During the brittle failure phase of coal structure（ GSI）,the coal samples become yielded and failed;the acoustic emission strength increases gradually and the permeability has a hysteresis increase and then increases to its maximum as a result of the full extension of fractures. During the plastic decrease phase of coal structure（ GSI）,the concave and convex parts of early-formed fractures are cut and corroded; the connectivity becomes weak and coal sam-ples are powdered gradually; at the same time,the acoustic emission count increases significantly but with less strength,and with the increase of strain,the stress curve becomes upturned which indicates the effect of re-compaction,and also the permeability has a notable decrease.

关 键 词：煤体结构 渗透率 地质强度指标(GSI) 声发射 煤层气 

分 类 号：P618.11[天文地球—矿床学]