塔里木盆地下志留统柯坪塔格组沉积和层序地层特征——以柯坪县阿恰剖面为例  

Sedimentary and sequence stratigraphic characteristics of the Lower Silurian Kepingtag Formation in Tarim Basin——Taking the Aqia profile in Keping County as an example

作　　者：王正和 张荣虎 岳勇[5] 余朝丰 杨钊 智凤琴 WANG Zhenghe;ZHANG Ronghu;YUE Yong;YU Chaofeng;YANG Zhao;ZHI Fengqin(Chengdu Center of China Geological Survey(Geosiciences Innovation Center of Southwest China),Chengdu,611230;Key Laboratory of Sedimentary Basin and Oil and Gas Resources,Ministry of Natural Resources,Chengdu,611230;PetroChina Hangzhou Research Institute of Geology,Hangzhou,310023;Research Center of Tarim Basin,PetroChina Research Institute of Petroleum Exploration and Development,Korla,Xinjiang,841000;Research Institute of Shanghai Branch of China National Offshore Oil Corporation Limited,Shanghai,200030)

机构地区：[1]中国地质调查局成都地质调查中心(西南地质科技创新中心),成都611230 [2]自然资源部沉积盆地与油气资源重点实验室,成都611230 [3]中国石油杭州地质研究院,杭州310023 [4]中国石油勘探开发研究院塔里木盆地研究中心,新疆库尔勒841000 [5]中海石油(中国)有限公司上海分公司研究院,上海200030

出　　处：《地质论评》2024年第3期932-944,共13页Geological Review

基　　金：国家自然科学基金委企业创新发展联合基金集成项目(编号:U22B6002);中国石油集团基础性前瞻性重大科技专项(编号:2023ZZ02)的成果。

摘　　要：基于不同的研究位置或区域,目前,塔里木盆地志留系柯坪塔格组三级层序划分方案不一,这制约了对该段地层区域构造—沉积演化及油气勘探方向的认识。笔者等结合露头、公开的钻井、地震及已有的研究成果,对柯坪阿恰地区的柯坪塔格组露头剖面沉积与层序特征进行了系统分析,认为:①阿瓦提凹陷西缘阿恰地区柯坪塔格组以混合水动力控制下的三角洲沉积体系为主,自下而上,下段为由粗至细再到粗的沉积旋回,中段与上段整体构成向上变粗的沉积旋回;②柯坪塔格组顶、底及内部的不整合面可将其分为2个三级层序,其下段构成第一个三级层序(SQ1),中段和上段构成第二个三级层序(SQ2);SQ1中低位体系域(LST)、海侵体系域(TST)及高位体系域(HST)均发育,SQ2中只发育TST和HST;③柯坪塔格组中段与下段的界线对应于晚奥陶世赫南特期全球冰期海平面下降所形成的不整合;④水动力条件不同,导致LST中以河流作用为主,HST中波浪与潮汐作用大于河流作用;⑤SQ2中的TST为区域性的优质盖层,与SQ1中的HST可构成良好的盖、储组合,故SQ1中的HST可作为该套地层中的首要勘探目标。Objectives:The third-order sequence division of the Lower Silurian Kepingtage Formation in the Tarim Basin was different based on different research locations or areas,which restricted the understanding of the regional tectonic—sedimentary evolution and the direction of oil and gas exploration of these strata.So it is necessary to analysis the sedimentary characteristics and divide the third-order sequence of these strata again.Methods:In order to reasonably divide its third-order sequence,we have combined with all data of outcrops,published wells and seismic,existing research results,the detailed analysis of the sedimentary and sequence characteristics of the outcrop of the Kepingtage Formation in Aqia area,Keping County.Results:①The Kepingtage Formation in Aqa area is mainly a delta sedimentary system controlled by mixed hydrodynamics dominated.From bottom to top,the lower member is a sedimentary cycle from fining-up to coarsingup,and the middle and upper members form a coarse-up sedimentary cycle as a whole.②The unconformity surfaces at the top,bottom and inside of the Kepingtage Formation can divide it into two third-order sequences.The lower member constitutes SQ1,with LST,TST and HST.The middle and upper members constitute SQ2,with only TST and HST.③The boundary between the middle and the lower members of the Kepingtage Formation may correspond to the unconformity formed by the sea level decline during the glacial period in the Late Ordovician Hernantian.④As the hydrodynamic conditions of different system tracts are different,the LST is dominated by river effect,while the wave and tide effect is greater than the river effect in HST.⑤TST in SQ2 is a regional highquality cap rock,which can form a good cap-reservoir combination with HST in SQ1.Therefore,HST of SQ1 in the western Awati sag can be the primary exploration target in this strata.Conclusions:In Aqia area,the Kepingtage Formation belongs to a delta sedimentary system formed with the mixed hydrodynamics,and it can be divided into two third

关 键 词：沉积特征 层序地层 柯坪塔格组 志留系 阿瓦提凹陷 塔里木盆地 

分 类 号：P618.13[天文地球—矿床学]