沁水盆地南部柿庄地区山西组三角洲平原聚煤模式  

Coal accumulation model in delta plain setting of Shanxi Formation in Shizhuang area,southern Qinshui basin

作　　者：张月 祝彦贺 邵龙义[2] 王存武 朱学申 刘芬 康世龙 ZHANG Yue;ZHU Yanhe;SHAO Longyi;WANG Cunwu;ZHU Xueshen;LIU Fen;KANG Shilong(CNOOC Research Institute Ltd.,Beijing 100028,China;College of Geoscience and Surveying Engineering,China University of Mining&Technology(Beijing),Beijing 100083,China)

机构地区：[1]中海油研究总院有限责任公司,北京100028 [2]中国矿业大学(北京)地球科学与测绘工程学院,北京100083

出　　处：《中国海上油气》2023年第4期56-65,共10页China Offshore Oil and Gas

基　　金：中国海洋石油有限公司“十四五”重大科技项目“陆上非常规天然气勘探开发关键技术(编号:KJGG-2022-1001)”、中国海洋石油有限公司综合科研“七年行动计划”课题“煤储层精细描述与产能主控因素研究(编号:2021OT-XNY09)”部分研究成果。

摘　　要：不同聚煤模式下控制的煤层分布规律制约着煤层气的勘探开发。为明确三角洲平原含煤岩系聚煤模式,选取沁水盆地柿庄地区山西组3号煤层及其下伏和上覆岩层为研究对象,在岩心观察、建立高分辨率层序格架的基础上,对含煤岩系沉积相进行划分。研究表明:①研究区山西组为三角洲平原沉积,自下而上呈现逐步海退、陆相作用增强、从北向南逐渐进积的过程。②三角洲平原中发育分流河道、天然堤、决口扇及分流间湾等沉积微相类型,在垂向上形成由砂岩、泥岩构成的煤层顶、底板,组成了4种类型复合砂体叠置模式。其中,分流间湾泥岩夹煤是对煤层气保存最优的叠置模式类型。③在泥炭沼泽发育过程中,初期的地势低洼处优先形成低位泥炭沼泽,但灰分产率较高,而后形成高位泥炭沼泽,形成厚煤层,灰分产率降低。泥炭沼泽发育前、发育过程及终止后三个阶段形成的空间组合共同组成了三角洲平原聚煤模式。该模式为三角洲平原煤层气的勘探开发提供地质理论依据。The exploration and development of coalbed methane are restricted by coal bed distribution which is controlled by different coal accumulation models.To ascertain the coal accumulation model of coal-bearing strata in delta plain setting,the sedimentary facies of coal-bearing strata which are obtained from the No.3 coal bed of Shanxi Formation in Shizhuang area,southern Qinshui basin and its underlying and overlying strata are classified on the basis of core observation and the high-resolution stratigraphic sequence framework.The results reveal that:①The Shanxi Formation in the study area developed delta plain,which showed a process of stepwise regression,continental enhancement,and gradual progradation from north to south.②The distributary channel,natural embankment,crevasse splay,and inter-distributary bay developing in the delta plain formed the roof and floor of coal bed,which composed four types of compound sand-body stacking patterns in the vertical direction.And of all the patterns,inter-distributary mudstones interbedded with coal is the optimal type for coalbed methane reservation.③During the process of peat bogs formation,low peat bogs were first formed in the initial low-lying areas with a high ash yield,while high peat bogs with thick coal beds were formed in areas with a low ash yield.The coal accumulation model which can provide geological theoretical basis for the exploration and development of coaled methane in delta plain was formed by the spatial combination of these peat bogs developed in the pre-formative stage,formation stage,and post-depositional stage.

关 键 词：含煤岩系 三角洲平原 聚煤模式 山西组 沁水盆地 柿庄地区 

分 类 号：P618.11[天文地球—矿床学]