【摘要】 煤层的物性特征与煤与瓦斯突出、煤层瓦斯含量密切相关,为降低复合煤层的煤与瓦斯突出的危险性、煤层瓦斯含量,分别采用低温液氮吸附试验、压汞试验、甲烷等温吸附/扩散试验对焦作矿区复合煤层中的软硬煤物性差异性进行研究。结果表明:软煤的BJH孔容及BET比表面积均大于硬煤;构造作用可使一部分可见孔或裂隙转化为中大孔,硬煤的孔隙联通性比软煤的孔隙联通性好。软煤中一端开放的细颈瓶型孔占的比例较大,造成软煤的退汞效率低,这是软煤易发生煤与瓦斯突出的重要原因之一;软煤的吸附常数a值稍大于硬煤,而比表面积却有显著差异,孔隙中吸附瓦斯不仅与比表面积有关,还与孔径大小、吸附层数及兰纳-琼斯势能有关;软煤的扩散系数大于硬煤,其衰减得比硬煤快,扩散系数与时间呈现出时变特性;在软硬分层进行现场取心实测煤层瓦斯含量时,应以软分层漏失量最小为基准采取抑制瓦斯漏失的措施,以实现煤层瓦斯含量的准确测定;在软分层进行瓦斯抽采时应适当加长抽采时间、减小钻孔间距,达到软分层消突效果。软硬分层的瓦斯含量与软硬煤的水分、孔隙率相关,孔隙率越大游离瓦斯含量越大,平衡水分抑制煤体瓦斯吸附,平衡水分越大其吸附量越小。如果软分层的瓦斯含量大于硬分层的瓦斯含量,在进行瓦斯抽采效果检验时,软分层是首选检验对象;如果软分层的瓦斯含量不大于硬分层的瓦斯含量,在进行瓦斯抽采效果检验时,软分层和硬分层应同时作为检验对象。更多还原

【Abstract】 This paper is devoted to quantitatively identify coal structure and study the distribution characteristics of coal structure in Hancheng H3 well group. The drilling coring data and the differences of logging response characteristics of coal seams with different coal structure are analyzed. The method of identifying coal structure with dual parameters of coal structure index( N) and ratio of deep lateral resistivity to micro resistivity R( LLD/MSFL) is established. According to the inversion model,and the logging interpretation of coal structure in 29 wells was completed,and the vertical distribution characteristics of coal structure were clarified. Furthermore,the stochastic modeling method is used to realize the three-dimensional visualization of the spatial distribution characteristics of coal structure using the Petrel2015 three-dimensional geological modeling software. The results show that in No.5 coal seam,N<40 and R<81 are ClassⅠcoal( primary-cataclastic coal),N<42 and 82<R<108 are ClassⅡcoal( cataclastic-fragmented coal),and 65<N<95 and R<95 are Class Ⅲ coal( fragmented-mylonitic coal). In No.11 coal seam,N<42 and R<70 are ClassⅠcoal( primary-cataclastic coal),28<N<47 and 72<R<110 are Class Ⅱcoal( cataclastic-fragmented coal),and 55<N<89 and 49<R<99 are Class Ⅲ coal( fragmented-mylonitic coal). The coal structure of No.5 coal seam in Hancheng H3 well group is mainly composed of Class Ⅲ coal and ClassⅠcoal,accounting for 43% and 37%,respectively.Class Ⅲ coal mainly distributes in the northeastern side of the study area and ClassⅠcoal distributes in the west and southeast of the study area.Class Ⅱ coal only accounts for 9.2%,and there is also a small amount of parting( 10.9%),and the thickness is thin. The coal structure of No.11 coal seam is mainly Class I coal,accounting for 62% and the thickness is thicker.Class II coal and Class III coal are less,accounting for 20.6% and 12.1% respectively.ClassⅡcoal is mainly distributed in the eastern part of the study area and Class Ⅲ coal is mainly distributed in the central part of the study area. The thickness of ClassⅡcoal and Class Ⅲ coal is thinner and the parting is relatively less( 5.5%). In general,the No.5 coal seam of Hancheng H3 well group is more affected by structure than No.11 coal seam. The coal is severely broken,and the structure coal is developed,which is unfavorable for coalbed methane exploitation.更多还原