陆表海背景下障壁海岸体系沉积层序及聚煤模式--以渤海湾地区晚古生代太原组为例  

Sequence stratigraphy and coal accumulation of barrier coastal system under epicontinental-sea environment: A case study of the Late Paleozoic Taiyuan Formation in Bohai Bay Area

作　　者：常嘉 陈世悦[1] 王琼 蒲秀刚[3] 杨怀宇[4] CHANG Jia;CHEN Shiyue;WANG Qiong;PU Xiugang;YANG Huaiyu(School of Geosciences,China University of Petroleum(East China),Qingdao 266580,China;The Third Institute of Geology and Mineral Resources of Shandong Province,Yantai 264003,China;PetroChina Dagang Oilfield Company,Tianjin 300280,China;Research Institute of Petroleum Exploration and Development,Shengli Oilfield Company,SINOPEC,Dongying 257015,China)

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [2]山东省地质矿产勘查开发局第三地质大队,山东烟台264003 [3]中国石油大港油田公司,天津300280 [4]中国石化胜利油田勘探开发研究院,山东东营257015

出　　处：《煤田地质与勘探》2021年第4期123-133,共11页Coal Geology & Exploration

基　　金：国家科技重大专项课题(2016ZX05006-007)。

摘　　要：渤海湾地区位于华北板块东部,是我国重要的煤炭产区,晚古生代发育多套可供工业开采的煤层,其中以陆表海背景下发育的海相煤层分布范围最广。为研究陆表海背景下障壁海岸体系沉积层序及聚煤模式,本文以渤海湾地区晚古生代太原组为研究对象,结合钻井及野外剖面资料,对该地区展开沉积学及层序地层学研究。在识别岩性及沉积相基础上,开展层序地层研究,在层序地层格架内揭示障壁海岸体系聚煤模式。太原组岩性以黄褐色、灰黑色泥岩及黄绿色、灰白色砂岩为主,夹数层海相灰岩及煤层。沉积相类型主要为潮坪相、潟湖相、障壁岛相及台地相。在障壁海岸体系背景下,基准面与沉积界面基本一致,层序界面多为沉积界面。根据沉积相转换面与下切谷冲刷面两类不整合面(SU)以及海侵方向转换面(TDS)可将太原组划分为3个三级层序Sq1、Sq2及Sq3。通过最大海泛面(MFS)与最大海退面(MRS)将三级层序划分为低位体系域、海侵体系域及高位体系域3个体系域,代表8个四级层序。Sq1时期,盆地内部地区未能提供稳定聚煤环境,煤层发育厚度较薄。Sq2时期,海平面升降对盆地内部影响增大,聚煤作用达到顶峰,煤层整体厚度增加并连接成片。Sq3时期,聚煤作用相对减弱,聚煤中心分布范围收缩,且孤立发育。统计钻井资料中煤层累积厚度可知,厚煤层发育主要集中在冀中坳陷东部、黄骅坳陷及济阳坳陷等地区。将研究区太原组聚煤模式划分为LST、TST早期、TST中期、TST晚期及HST五期演化过程。受可容空间增长速率及泥炭堆积速率的控制,泥炭坪及潟湖为有利聚煤中心。The Bohai Bay Area,located in the east of North China,is an important area for coal production in China.There are many coal seams available for industrial exploitation in the Late Paleozoic,among which the marine coal seams developed in the epicontinental-sea environment are the most widely distributed.In order to study the sedimentary sequence and coal accumulation model of the barrier coastal system in the epicontinental-sea environment,this paper studies the sedimentology and sequence stratigraphy of the Late Paleozoic Taiyuan Formation in the Bohai Bay Area,combining with drilling and field profile data.Based on the identification of lithology and sedimentary facies,the study of sequence stratigraphy is carried out to reveal the coal accumulation model of the barrier coastal system in the sequence stratigraphic framework.Taiyuan Formation is mainly composed of yellowish brown,gray black mudstone and yellow green and gray white sandstone,with several layers of marine limestone and coal seams.The sedimentary facies are mainly tidal flat facies,lagoon facies,barrier island facies and platform facies.Against the background of the barrier coastal system,the base level and the sedimentary interface are basically the same,and the sequence boundary is mostly sedimentary interface.According to the two types of subaerial unconformities(SU)including sedimentary facies transition surface and incised valley scour surface and transgressive direction transition surface(TDS),Taiyuan Formation can be divided into Sq1,Sq2 and Sq3.The third order sequence is divided into LST,TST and HST system tracts by maximum flooding surface(MFS)and maximum regression surface(MRS),representing eight fourth order sequences.During the period of Sq1,the internal area of the basin fails to provide a stable coal accumulation environment,and the thickness of the coal seams is relatively thin.During the Sq2 period,the influence of sea level on the Area increases,the coal accumulation reaches the peak,and the overall thickness of the coal seams incr

关 键 词：障壁海岸体系 层序地层 聚煤模式 渤海湾地区 晚古生代 

分 类 号：P531[天文地球—古生物学与地层学]