乍得Bongor盆地北部斜坡带P组沉积特征分析

乍得西南部的Bongor盆地是受中非剪切带影响发育的中—新生代被动裂谷盆地。在P组沉积时期,Bongor盆地处于裂陷湖盆初始发育阶段,总体处于持续水进扩张过程,发育陆相扇三角洲-湖相沉积。岩心观察结果表明,P组沉积物具有近源、深水、粗屑、重力流为主以及持续水进等特征。结合岩心、录井、测井及地震资料分析,明确Bongor盆地发育扇三角洲相、湖泊相及重力流沉积,其中扇三角洲相发育扇三角洲前缘和前扇三角洲亚相,扇三角洲前缘亚相发育水下分流河道、河口坝、水下分流河道间和席状砂微相。以Bongor盆地北部斜坡带Baobab北次凹为例,进行构造-沉积耦合分析,认为其存在2大物源体系:长轴方向发育三角洲相沉...

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Bibliographic Details
Published in油气地质与采收率 Vol. 25; no. 3; pp. 29 - 35
Main Author 方正;季汉成;徐刚;杨轩;杜业波;王佳意
Format Journal Article
LanguageChinese
Published 中国石油大学(北京)地球科学学院,北京,102249%中国石油海外勘探开发公司,北京,100034%中国石油勘探开发研究院,北京,100083 2018
Subjects
裂谷盆地沉积体系扇三角洲构造-沉积耦合Bongor盆地
扇三角洲
rift basin
sedimentary system
Bongor Basin
沉积体系
fan delta
structure-sedimentation coupling
构造-沉积耦合
Bongor盆地
裂谷盆地
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ISSN1009-9603
DOI10.13673/j.cnki.cn37-1359/te.2018.03.004

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Summary:乍得西南部的Bongor盆地是受中非剪切带影响发育的中—新生代被动裂谷盆地。在P组沉积时期,Bongor盆地处于裂陷湖盆初始发育阶段,总体处于持续水进扩张过程,发育陆相扇三角洲-湖相沉积。岩心观察结果表明,P组沉积物具有近源、深水、粗屑、重力流为主以及持续水进等特征。结合岩心、录井、测井及地震资料分析,明确Bongor盆地发育扇三角洲相、湖泊相及重力流沉积,其中扇三角洲相发育扇三角洲前缘和前扇三角洲亚相,扇三角洲前缘亚相发育水下分流河道、河口坝、水下分流河道间和席状砂微相。以Bongor盆地北部斜坡带Baobab北次凹为例,进行构造-沉积耦合分析,认为其存在2大物源体系:长轴方向发育三角洲相沉积,短轴方向存在2种受构造控制的沉积模式,分别为在构造调节带(断层生长连接点)发育扇三角洲相沉积,在非构造调节带发育重力流沉积。
Bibliography:rift basin;sedimentary system;fan delta;structure-sedimentation coupling;Bongor Basin
Bongor Basin,located in the south-west of the Republic of Chad,is a Mesozoic-Cenozoic passive rift basin evolved under the influence of shear zone of Central Africa Rift.Bongor Basin was in the beginning of a rift lacustrine basin development and always kept expansion through a continuous transgression progress during the sedimentation of the P For-mation,during which terrestrial fan delta-lacustrine deposited.The results of core observation show that the P Formation are characterized by near-provenance,deep-water,coarse-grain,gravity-flow and consecutive transgression sediments.Combined with the indication of well-logging and seismic data,it is determined that fan delta,lacustrine and gravity flow develop in the study area.The fan delta consists of fan delta front and pre-fan delta sub-facies,and the fan delta front con-sists of submarine distributary channel,estuary bar,interdistributary and sand sheet.Taking the sub-sag in
ISSN:1009-9603
DOI:10.13673/j.cnki.cn37-1359/te.2018.03.004