韩城矿区煤层气成藏条件及类型划分  

Coalbed methane accumulation characteristics and type classification in Hancheng mining area

作　　者：郭晨[1] 夏玉成[1] 卫兆祥 孙学阳[1] 代革联[1] 王社荣 申建[3] 任亚平[1] GUO Chen;XIA Yucheng;WEI Zhaoxiang;SUN Xueyang;DAI Gelian;WANG Sherong;SHEN Jian;REN Yaping(College of Geology and Environment,Xi＇an University of Science and Technology,Xi＇an 710054,China;Hancheng Mining Company Limited,Shaanxi Coal and Chemical Industry Group Company Limited,Haneheng 715400,China;Key Laboratory of CBM Resources and Reservoiring Process,China Univer-sity of Mining and Technology,Xuzhou 221116,China)

机构地区：[1]西安科技大学地质与环境学院,陕西西安710054 [2]陕西煤业化工集团韩城矿业有限公司,陕西韩城715400 [3]中国矿业大学煤层气资源与成藏过程教育部重点实验室,江苏徐州221116

出　　处：《煤炭学报》2018年第B06期192-202,共11页Journal of China Coal Society

基　　金：陕西煤业化工集团科研基金资助项目(2015SMHKJ-B-J-08);中国博士后科学基金面上资助项目(2018M631181)

摘　　要：韩城矿区是我国最早实现煤层气商业开发的区块之一,分析前期煤层气勘探开发试验成果,有助于进一步认识煤层气成藏机理,提升开发效率。从含气性和渗透性两个关键储层参数、以及构造变形和水文地质条件两大宏观地质因素出发,揭示了煤层气成藏地质条件及其耦合作用,并划分了成藏类型:韩城矿区基本构造形态为一走向NE,倾向NW的单斜构造,地下水在东南边浅部接受补给并向西北流动,流动过程中径流强度逐渐减弱,在中深部形成水力封堵造成煤层气富集。煤层含气量总体沿地层倾向增大,边浅部在活跃地下水补给条件下生成次生生物气,造成含气量局部增高。构造曲率显示边浅部构造带和东泽村构造带是煤层变形最强的两个区域,受其控制,边浅部煤级局部可达贫煤,且分布范围与高变形区域基本吻合,揭示存在动力变质作用。400 m和800 m两个深度界限划分了含气量和渗透率的垂向分异格局,在此基础上区分出3种煤层气成藏类型,分别为边浅部隆起断裂带逸散型,深部斜坡带富集型以及中部过渡型,中部过渡型含气量与渗透率可实现优势叠合,煤层气开发条件最好,实际产能情况与之相符。Hancheng mining area is a hot spot of coalbed methane（ CBM） development and research in China.A comprehensive analysis of the data acquired from the CBM exploration and exploitation will improve the CBM accumulation theory and promote the CBM development.On the basis of the key reservoir parameters of gas content and permeability,and the macro-scale geological conditions of tectonic deformation and hydrogeology,the CBM accumulation conditions and their coupling effect are revealed in this study,and the CBM accumulation types are classified.The following conclusions are obtained： the Hancheng mining area is located within a monoclinal structure with northeast trend andnorthwest dip.The groundwater recharges from the shallow strata in southeast,and then flows to the northwest.The hydrodynamic intensity weakens with increasing depth,and results in the hydro-sealing effect and CBM accumulation in the deep coal seam.The gas content of coal seams increases along the dip direction generally,secondary biogenic gas generates in the shallow zone as a result of the active groundwater,and results in the high gas content in some local area.Based on the structural curvature analysis,the shallow tectonic zone and Dongzecun tectonic zone deform the coal seam severely.Under its control,meager coal occurs locally in the shallow area,which coincides with the highly deformed area,indicating the dynamic metamorphism of coal seams in the shallow strata.The critical depth of 400 m and800 m controls the vertical differences of gas content and permeability,and three CBM accumulation types can be identified including the gas loss type in the shallow tectonic zone,the gas enrichment type in the deep slope zone,and the middle transitional type.The middle transitional zone realizes the optimum match between gas content and permeability and favors the CBM development,which is verified by the actual CBM productivity.

关 键 词：韩城矿区 煤层气 构造曲率 动力变质 次生生物气 成藏类型 

分 类 号：P618.11[天文地球—矿床学]