河套盆地临河坳陷白垩纪-古近纪沉积环境演化及油气地质意义  

Sedimentary evolution and petroleum potential of the Cretaceous to Paleogene in Linhe depression,Hetao Basin

作　　者：陆鹿[1,2] 陈树光 李壮福[1,2] 秦勇[1,2] 屈争辉[1,2] 沈玉林[1,2] Lu Lu;Chen Shu-Guang;Li Zhuang-Fu;Qin Yong;Qu Zheng-Hui;Shen Yu-Lin(Key Laboratory of Coalbed Methane Resources and Reservoir Formation Process(Ministry of Education of China),China University of Mining and Technology,Jiangsu Xuzhou 221116,China;School of Resources and Geosciences,China University of Mining and Technology,Jiangsu Xuzhou 221116,China;Exploration and Development Research Institute of Huabei Oil Field Company,Petro China,Hebei Renqiu 062550,China)

机构地区：[1]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 [2]中国矿业大学资源与地球科学学院,江苏徐州221116 [3]中国石油华北油田公司勘探开发研究院,河北任丘062550

出　　处：《古地理学报》2022年第2期308-331,共24页Journal of Palaeogeography：Chinese Edition

基　　金：中国石油天然气股份有限公司科技攻关课题(编号:2019D-0815);中国矿业大学第十三批青年教师“启航计划”;2021年江苏省“双创计划”(编号:JSSCBS20211215)联合资助

摘　　要：河套盆地沉积环境演化的研究程度较低,尤其是针对具有重要油气勘探潜力的临河坳陷白垩系和古近系。通过对地震和钻井资料的详细分析,对河套盆地临河坳陷白垩系和古近系沉积演化开展系统研究,并探讨其油气地质意义。结果表明:(1)白垩纪和古近纪,河套盆地临河坳陷处于亚热带干旱—半干旱气候条件,沉积水体整体富氧但局部贫氧—厌氧,并且淡水和半咸水环境交替出现。(2)坳陷内的白垩系和古近系共发育5类沉积相,包括冲积扇、辫状河、辫状河三角洲、扇三角洲及湖泊相,又进一步划分为12类沉积亚相及22类沉积微相。坳陷西北侧断控构造活动较强,地形高差较大,发育冲积扇、扇三角洲、湖泊沉积体系;东南侧构造活动弱,地形较缓,发育辫状河、辫状河三角洲、湖泊沉积体系。各期沉积格局整体相似,仅表现在盆缘扇体和盆内湖相沉积规模的此消彼长。(3)坳陷内的白垩系和古近系沉积作用表现为“弱幕式构造主控下的干旱浅水双物源沉积”特征。在盆地发育的初期,构造活动较强,但盆地规模较小且水体较浅,两侧碎屑物质快速向盆内推进,并在盆地中心汇合,形成“满盆砂”的沉积格局。随着构造活动减弱和水平面快速上升,碎屑物质供应不足,湖泊的沉积和改造作用占据主导,从而形成以湖泊相占优势的沉积格局。(4)坳陷内的沉积相带控制着砂体的宏观发育规模、叠置关系和垂向演变,进一步决定了有效储集层的空间分布特征。在沉积相带和断裂作用双重主控因素下,坳陷内的白垩系和古近系有利储集层多分布于以滨—浅湖和三角洲前缘沉积为主并且断层发育的中央断垒带。The study on the sedimentary evolution of the Hetao Basin is relatively insufficient,espe-cially for the Cretaceous and Paleogene strata in the Linhe depression,which has important oil and gas ex-ploration potential.In this article,based on sedimentology,mineralogy,petrology,geochemistry,field and drilling data,we performed a systematic sedimentary research on the Cretaceous to Paleogene strata in the Linhe depression and to explore its petroleum significance.The results show that:(1)From the Creta-ceous to Paleogene,the Linhe depression in the Hetao Basin was characterized by sub-tropical arid and semi-arid climate,an overall oxygen-rich water body but locally anaerobic-anaerobic,and alternation of fresh water and brackish water environments.(2)There are five types of sedimentary facies in the Creta-ceous to Paleogene strata,including alluvial fan,braided river,braided river delta,fan delta,and la-custrine facies,which are further divided into 12 types of sedimentary subfacies and 22 types of sedimen-tary microfacies.In the northwestern depression,the alluvial fan-delta-lacustrine sedimentary system was developed due to strong fault activity and high topographic relief.In the southeastern depression,a rela-tively weak tectonic activity and low topographic relief resulted in a braided river-braided river delta-lacus-trine sedimentary system.The sedimentary pattern of each period is similar and only shows the variation of the fan-lacustrine boundary.(3)The Cretaceous to Paleogene Linhe Formation was characterized by arid and semi-arid,shallow water,dual provenances controlled by weak episodic tectonic activity.In the early stage of basin development,the tectonic activity was strong,but the basin was small and shallow.The clastic materials from both sides of basin margin rapidly advanced into and even converged in the center of the basin,forming a basin filled up by sands.With the weakening of tectonic activity and the rapid rise of lake water in the late stage,the clastic materials supply was insufficient to fill

关 键 词：沉积相 储集层 白垩系—古近系 临河坳陷 河套盆地 

分 类 号：P531[天文地球—古生物学与地层学]