陆相断陷湖盆重力流湖底扇沉积与地震响应特征分析:以渤海湾盆地霸县凹陷古近系沙河街组为例  

Sedimentary and seismic responses characteristics of gravity flow sublacustrine fans in lacustrine rift basin:case study on the Paleogene Shahejie Formation in Baxian sag,Bohai Bay Basin

作　　者：张自力[1,2,3] 李琦 朱筱敏[3] 谈明轩[4] 张锐锋 曹兰柱 李凤勋 单帅强 ZHANG Zili;LI Qi;ZHU Xiaomin;TAN Mingxuan;ZHANG Ruifeng;CAO Lanzhu;LI Fengxun;SHAN Shuaiqiang(PetroChina Southwest Oil&Gasfield Company Exploration and Development Research Institute,Chengdu 610051,China;School of Ocean Sciences,China University of Geosciences(Beijing),Beijing 100083,China;College of Geosciences,China University of Petroleum(Beijing),Beijing 102249,China;College of Oceanorgraphy,Hohai University,Nanjing 210098,China;PetroChina Huabei Oilfield Company,Hebei Renqiu 062552,China;Petroleum Exploration&Production Research Institute,SINOPEC,Jiangsu Wuxi,214126,China)

机构地区：[1]中国石油西南油气田分公司勘探开发研究院,四川成都610051 [2]中国地质大学(北京)海洋学院,北京100083 [3]中国石油大学(北京)地球科学学院,北京102249 [4]河海大学海洋学院海洋地质研究所,江苏南京210098 [5]中国石油华北油田分公司,河北任丘062552 [6]中国石化石油勘探开发研究院无锡石油地质研究所,江苏无锡214126

出　　处：《古地理学报》2023年第5期1049-1068,共20页Journal of Palaeogeography：Chinese Edition

基　　金：国家重点研发计划项目(编号:2019YFC0605400)资助。

摘　　要：陆相断陷湖盆各构造演化阶段发育丰富的重力流湖底扇沉积。本次以渤海湾盆地霸县凹陷沙河街组为例,通过三维地震精细解释并结合钻井取心及岩/电特征分析,探讨陆相断陷湖盆重力流扇体成因类型和分布规律,总结沉积模式。研究表明,霸县凹陷古近系沙河街组发育滑塌型重力流湖底扇、洪水型重力流湖底扇、风暴重力流湖底扇3种成因类型和5种具体样式。根据重力流湖底扇体物源、搬运路径上底型结构和平面分布特征,可以划分为物源区—断裂陡坡带—湖底扇、(进积型)三角洲—坡折带—湖底扇、水下低凸起(滩坝)-湖底扇3种平面组合类型。并建立了断陷湖盆初始断裂期风暴重力流湖底扇、强烈断陷期洪水型湖底扇、稳定裂陷期洪水型湖底扇、断后回返期滑塌型湖底扇4种沉积模式。认为:断陷湖盆各构造演化阶段具有不同成因类型的重力流湖底扇,重力流湖底扇的触发机制主要与斜坡区三角洲失稳、阵发性的洪水及湖浪作用有关。重力流湖底扇的结构和空间分布受控于断层活动和古湖盆底型结构,扇体规模主要受控于触发机制。深湖—半深湖区形成的被暗色泥岩包裹的湖底扇体具有良好的生储盖配置,是油气勘探的甜点区。基于单井资料分析下的地震属性(切片)分析能够有效地指导薄层砂岩勘探。Abundant sublacustrine fan(SLF)gravity flow deposits are developed in various tectonic evolution stages of lacustrine rift basins.Through 3D seismic fine interpretation combined with drilling/logging analysis,the genetic type and distribution of gravity flow fans in lacustrine rift basins are discussed and the depositional models are summarized for the Shahejie Formation of the Baxian Sag,Bohai Bay Basin.The research shows that three genetic types include slumping-,flood-,and storm-induced gravity flow SLF are developed in the Paleogene Shahejie Formation,and can be further divided into five specific types.Based on the sediment source of gravity flow SLF,bottom structures of the sag on the sediment transport path,and plane distribution characteristics between them,it can be divided into three plane combination types:provenance area-fault steep slope zone-SLF,(progradational)delta-slope break zone-SLF,underwater low bulge(beach bar)-SLF.Four depositional models are established including storm gravity flow SLF in the initial rift period,flood SLF in the strong rift period,flood SLF in the stable rift period,and slump SLF in the post rift return period.The study shows that gravity flow SLF deposits of different genetic types are developed in each tectonic evolution stage of lacustrine rift basin.The triggering mechanism of gravity flow SLF is mainly related to delta instability in slope area,paroxysmal flood and lake wave action.The architecture and distribution of gravity flow SLF are controlled by fault activity and bottom structures of the sag,and its size is mainly controlled by triggering mechanism.The gravity flow SLF wrapped by dark mudstone and oil shale formed in deep and semideep lake has good source reservoir cap rock configuration and oil/gas accumulation conditions,which is a sweet spot for oil and gas exploration.Seismic slice analysis based on well data can effectively guide the exploration of thin sandstone sheets.

关 键 词：霸县凹陷 古近系 重力流沉积 成因分析 地震响应 沉积模式 

分 类 号：TE122.2[石油与天然气工程—油气勘探]