四川盆地奉节地区上古生界古隆起特征及地质意义  

Characteristics and geological significance of Upper Paleozoic paleo-uplift in Fengjie area,Sichuan Basin

作　　者：杨荣军[1,2] 彭平 张静 叶茂 文华国 YANG Rongjun;PENG Ping;ZHANG Jing;YE Mao;WEN Huaguo(PetroChina Research Institute of Petroleum Exploration&Development-Northwest,Lanzhou 730020,China;Research Center of Sichuan Basin,PetroChina Research Institute of Petroleum Exploration&Development,Chengdu 610041,China;Research Institute of Exploration and Development,PetroChina Southwest Oil&Gas Field Company,Chengdu 610041,China;Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]中国石油勘探开发研究院西北分院,兰州730020 [2]中国石油勘探开发研究院四川盆地研究中心,成都610041 [3]中国石油西南油气田公司勘探开发研究院,成都610041 [4]成都理工大学沉积地质研究院,成都610059

出　　处：《岩性油气藏》2021年第4期1-9,共9页Lithologic Reservoirs

基　　金：中国石油西南油气田分公司四川盆地勘探重大项目“川东石炭系天然气地质条件深化研究与区带目标优选”(编号:XNS14NH2019-009)资助。

摘　　要：四川盆地东部地区边缘带上古生界构造复杂,对地层格架及地质规律认识不清,尤其对石炭系残余地层分布及沉积相展布认识欠缺,影响了该区的勘探开发。基于区域地质背景,结合新钻井、新三维地震数据及野外露头资料,首次提出了在奉节—云阳一带发育晚古生代持续古隆起(奉节古隆起)的认识;通过地震模型正演,确定了研究区志留系—泥盆系—石炭系地震反射特征,对奉节古隆起进行了刻画;通过研究古地貌控制下的石炭系地层识别及分布特征、构造演化,分析了石炭系油气成藏的条件,对石炭系有利天然气勘探区带进行预测评价。研究认为:奉节古隆起位于开江古隆起东侧约95 km处,与开江古隆起近于平行,整体近南北向,略偏东,其南北轴向长度约79 km,东西向宽度不等,三维区内平均宽度14 km;在开江古隆起和奉节古隆起的联合约束下,研究区的构造演化可以分为5个阶段:泥盆纪低位期、石炭纪低位期、石炭纪海进—高位期、石炭纪海退期和二叠纪海进期;由于奉节古隆起带长期持续演化,可以形成石炭系地层剥蚀带,随着地层埋深加大,在古隆起周缘的石炭系与志留系泥岩侧向对接,在油气充注前形成地层圈闭,后期经过多期构造影响,仍可能在现今的向斜-斜坡区保存为含气圈闭,可以作为石炭系天然气勘探的远景区。该认识为四川盆地东部石炭系天然气扩展勘探新领域提供了支撑。The stratigraphic structure of Upper Paleozoic in the marginal zone of the eastern Sichuan Basin is complex,and the stratigraphic framework and geological laws are not well understood,especially the limited understanding of the distribution of Carboniferous residual strata and sedimentary facies,which restricts the exploration and development in this zone.Based on the regional geological background,combined with the data of new drilling,new 3D seismic and wild outcrops information,a new understanding that there is a sustained paleo-uplift in Late Paleozoic named Fengjie paleo-uplift in Fengjie-Yunyang area was proposed firstly.In terms of the seismic model forward,the seismic reflection characteristics of Silurian-Devonian-Carboniferous were determined,and the Fengjie paleo-uplift was characterized.By studying the identification,distribution characteristics and tectonic evolution of Carboniferous strata under the control of paleogeomorphology,the analysis of hydrocarbon accumulation conditions of Carboniferous was completed and the favorable gas exploration zone of Carboniferous was predicted and evaluated.The studies suggest that Fengjie paleo-uplift is located about 95 km to the east of Kaijiang paleo-uplift,which is nearly parallel to Kaijiang paleo-uplift.Its overall trend is nearly north-south and slightly east,and the length of north-south axis is about 79 km,however,the width varies from east to west and the average is 14 km in 3D seismic area.Under the joint constraints of Kaijiang paleo-uplift and Fengjie paleo-uplift,the tectonic evolution of the study area can be divided into five stages:Devonian lowstand,Carboniferous lowstand,Carboniferous transgression-highstand,Carboniferous regression and Permian transgression.Because of the longterm continuous evolution of Fengjie paleo-uplift belt,the Carboniferous strata denudation zone can be formed,then with the increase of burial depth,the Carboniferous strata around the paleo-uplift was lateral docking with Silurian mudstone,and the stratigraphic traps woul

关 键 词：石炭系 黄龙组 地层-构造复合气藏 晚古生代 奉节古隆起 四川盆地东部 

分 类 号：TE122.3[石油与天然气工程—油气勘探]