不同阶煤孔隙结构与流体特性的核磁共振试验研究  

Nuclear magnetic resonance experimental study on pore structure and fluid characteristics of coal at different ranks

作　　者：杨明 柳磊[2] 张学博 毛俊睿 柴沛[2] YANG Ming;LIU Lei;ZHANG Xuebo;MAO Junrui;CHAI Pei(State Collaborative Innovation Center of Coal Work Safety and Clean-efficiency Utilization,Jiaozuo Henan 454003,China;School of Safety Science and Engineering,Henan Polytechnic University,Jiaozuo Henan 454003,China;State Key Laboratory Cultivation Base for Gas Geology and Gas Control,Jiaozuo Henan 454003,China)

机构地区：[1]煤炭安全生产与清洁高效利用省部共建协同创新中心,河南焦作454003 [2]河南理工大学安全科学与工程学院,河南焦作454003 [3]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,河南焦作454003

出　　处：《中国安全科学学报》2021年第1期81-88,共8页China Safety Science Journal

基　　金：国家自然科学基金资助(51704099);中国工程科技发展战略河南研究院咨询研究项目(2020HENZDB02);河南省高校基本科研业务费专项资金资助(NSFRF200317);河南省高等学校青年骨干教师培养计划(2020GGJS053)。

摘　　要：为探究煤储层结构及内部流体分布的特征,以不同区域的10组煤样为研究对象,基于饱水、离心及低场核磁共振系统,开展煤在不同状态下的低场核磁共振试验,在常规的单T_(2)截止值基础上,提出利用双T_(2)截止值,区分煤中流体的不可采出流体、毛管束缚流体及可动流体;搭建流体饱和度的模型,研究不同阶煤的孔隙结构特征与流体特性。结果表明:随着煤阶的升高,微小孔比例逐渐增大、吸附孔孔吼占比由51.77%增至90.19%,中大孔比例逐渐减小、渗流孔孔吼占比由48.23%降为9.81%;随着煤阶的降低,孔隙之间的连通性变好,渗透率由0.03 mD增至1.88 mD。煤样的孔隙度范围为0.73%~11.50%,T_(2CI)与T_(2CII)的主要分布在0.17~2.31、0.97~15.70 ms,相应的饱和度分布在4.21%~53.33%、34.67%~66.60%、6.19%~37.84%。In order to explore characteristics of coal reservoir structure and internal fluid distribution,with 10 sets of coal samples from different regions as research objects,low-field nuclear magnetic resonance tests of coal under different conditions were carried out by using saturated,centrifugal and lowfield nuclear magnetic resonance system.Based on conventional single T_(2) cutoff value,double T_(2) cutoff value was proposed to be used to distinguish non-recoverable fluid,capillary bound fluid and movable fluid in coal.Then,a fluid saturation model was established,and pore structure and fluid characteristics of coal at different ranks were studied.The results show that with increase of coal rank,proportion of micro pores gradually increases,and that of adsorption pore throat increases from 51.77%to 90.19%,while that of medium and large ones gradually decrease with seepage pore throat dropping from 48.23%to 9.81%.However,as coal rank decreases,connectivity between pores becomes better,and permeability increases from 0.03 mD to 1.88 mD.Moreover,porosity of coal samples ranges from 0.73%to 11.50%,main distributions of T_(2CI) and T_(2CII) are 0.17~2.31 ms and 0.97-15.70 ms,and corresponding saturation distribution is 4.21%-53.33%,34.67%-66.60%,and 6.19%-37.84%.

关 键 词：孔隙结构 流体特性 低场核磁共振 截止值 流体饱和度 

分 类 号：X936[环境科学与工程—安全科学]