湖南涟源凹陷早石炭世煤系气共生组合特征与有利层段优选  

Combination characteristics and favorable intervals of Early Carboniferous coal measure gas of Lianyuan sag,Hunan province

作　　者：朱文卿 郗兆栋 唐书恒[2] 龚明辉 王克营 ZHU Wenqing;XI Zhaodong;TANG Shuheng;GONG Minghui;WANG Keying(The Coal Geological Exploration Institute of Hunan Province,Changsha 410014,China;School of Energy Resource,China University of Geosciences(Beijing),Beijing 100083,China)

机构地区：[1]湖南省煤炭地质勘查院,湖南长沙410014 [2]中国地质大学(北京)能源学院,北京100083

出　　处：《中国矿业》2021年第8期180-187,共8页China Mining Magazine

基　　金：国家科技重大专项资助(编号:2017ZX05035);湖南省国土资源厅科研项目资助(编号:2015-01)。

摘　　要：湖南涟源凹陷早石炭世煤系地层具有煤层-煤系页岩-煤系砂岩垂向上相互叠置、平面上广泛分布的特征,显示出较好的煤系气兼探合采前景,然而目前尚缺乏该区煤系非常规天然气地质特征整体研究。本文以早石炭世测水组为研究对象,基于研究区典型钻孔的岩相组合及物性、含气性等实验分析,讨论了涟源凹陷煤系气共生组合模式及潜在的有利煤系气层段。结果表明:涟源凹陷测水组发育5种岩相组合类型,对应滨外陆棚、障壁-潮坪、障壁-沼泽、潟湖-沼泽和潮坪-沼泽沉积环境,以单源双储、双源双储、双源三储3类煤系气共生组合模式为主。基于分级加权法认为测水组下段上部为有利的勘探层段,以煤层为主要烃源岩、砂岩为主要储集层的煤层气-煤系砂岩气组合模式最为有利,集中分布于涟源凹陷中部一带。煤层累计厚度及其含气性对涟源凹陷煤系气藏起关键作用。The Carboniferous coal measures in Lianyuan sag of Hunan province are characterized by vertical superposition of coal seams,shale and sandstones,horizontal wide distribution and mutual superposition,which has a good prospect of exploration and production of coal measures gas.However,there is still a lack of research on the geological characteristics of unconventional natural gas from an overall perspective.Taking the Early Carboniferous Ceshui formation as the research object,based on the lithofacies assemblage and experimental analysis of physical properties and gas bearing properties of typical wells in the study area,this paper discusses the symbiotic combination mode of coal measure gas and potential favorable coal measure gas intervals in Lianyuan sag.The results show that there are five types of lithofacies assemblage corresponding to the depositional environments of offshore shelf,barrier-tidal flat,barrier-swamp,lagoon-swamp and tidal flat-swamp and three types of coal measure gas assemblage models corresponding to the“single source and two reservoirs”and“two source and two reservoirs”and“two source and three reservoirs”in the Ceshui formation of Lianyuan sag.Based on the hierarchical weighting method,the upper part of the lower member of the Ceshui formation is considered as a favorable exploration interval.The coal seam as the main source rock and sandstone as the main reservoir is the most favorable,which concentrated in the central area of Lianyuan sag.The cumulative thickness of coal seam and its gas bearing property play a key role in coal measures gas reservoir in Lianyuan sag.

关 键 词：早石炭世 煤层气 页岩气 致密砂岩气 涟源凹陷 

分 类 号：P631.8[天文地球—地质矿产勘探]