淮南煤田煤系页岩气储集空间特征及其岩相控制作用  

Reservoir Characteristics and Their Lithofacies Controlling Effect of Coal-Bearing Mudstone in Huainan Coal Field

作　　者：徐宏杰[1] 胡宝林[1] 郑建斌[1] 刘会虎[1] 张文永[2] 郑凯歌[1] 

机构地区：[1]安徽理工大学地球与环境学院,安徽淮南232001 [2]安徽省煤田地质局,合肥230088

出　　处：《吉林大学学报（地球科学版）》2017年第2期418-430,共13页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(41402140;41302129);安徽省页岩气资源调查评价项目(2012-g-17);安徽省自然科学基金项目(1408085QE88)~~

摘　　要：海陆过渡相煤系泥页岩广泛分布,具有良好的天然气资源潜力。以淮南煤田煤系泥页岩为研究对象,运用X射线衍射、扫描电镜等分析手段,对淮南煤田煤系地层泥页岩的矿物学、岩相、储层特征等方面进行相关测试,并探讨了泥岩岩相对页岩气储集空间的控制作用。研究表明:淮南煤田煤系泥页岩矿物成分中黏土矿物含量多、自生非黏土矿物相对较少,致使岩石脆性降低并对压裂裂缝产生具有负效应,但部分菱铁矿的存在可能起改善作用;存在花斑状高岭石泥岩、浅灰色高岭石泥岩、鲕状泥岩、暗色泥岩、粉砂质泥岩等5种岩相。泥页岩储层裂缝包括层面剪切缝、有机质演化异常压力缝、层间页理缝、构造裂缝等宏观类型和与石英和高岭石有关的微裂缝类型;泥页岩孔隙包括化石孔、粒间孔、粒内孔和晶间孔及可能的有机质孔等类型,为页岩气赋存提供了储集空间。不同沉积环境下的泥岩岩相不同,进而决定了矿物成分特征与有机质相对含量,对泥页岩储集空间起主要控制作用。Coal measure shale of marine-terrigenous facies is widely distributed with considerable natural gas resource potential.Taking the Carboniferous-Permian coal measures in Huainan coal field as an example,the mineralogical features,lithofacies characteristics and reservoir characteristics were tested by X-ray diffraction（XRD）and scanning electron microscopy（SEM）,and the controlling effect on shale gas reservoir space of mudstone facies were analyzed.The results show that the mineral composition is dominantly clay minerals with few authigenic clay minerals.Five lithofacies,i.e.kaolinite mudstone with granophyric texture,light gray kaolinite mudstone,oolitic mudstone,dark mudstone and silty mudstone,were identified in the coal measure strata.Five types of reservoir macrofracture spaces,including shearing fracture along bedding plane,abnormal pressure fracture for organic matter evolution,interlayer lamellation fracture,structural fracture,and micro-fracture with quartz and kaolinite,and some pore types as fossil pore,interparticle pore,intragranular pore,inter-crystalline pore and possible organic matter pore.There are different lithofacies types under different sedimentary environments,and it determines their mineral composition characteristics and the organic matter content,further determines the types of reservoir pore space,and controls the development of mudstone fracture.

关 键 词：煤系页岩气 储集空间 泥页岩 孔隙与裂缝 淮南煤田 

分 类 号：TE122.2[石油与天然气工程—油气勘探]