乍得Doseo盆地白垩纪沉积充填演化及对油气成藏的控制作用  

Cretaceous Sedimentary Filling Evolution and Its Control on Hydrocarbon Accumulation in Doseo Basin,Chad

作　　者：陈全红 赵红岩 李全 张科 阳怀忠 陈经覃 李克永 郭家铭 饶勇 CHEN QuanHong;ZHAO HongYan;LI Quan;ZHANG Ke;YANG HuaiZhong;CHEN JingTan;LI KeYong;GUO JiaMing;RAO Yong(CNOOC International Limited,Beijing 100028,China;School of Geology and Environment,Xian University of Science and Technology,Xi’an 710054,China;Shaanxi Provincial Key Laboratory of Geological Support for Coal Green Exploitation,Xi’an 710054,China)

机构地区：[1]中国海洋石油国际有限公司,北京100028 [2]西安科技大学地质与环境学院,西安710054 [3]陕西省煤炭绿色开发地质保障重点实验室,西安710054

出　　处：《沉积学报》2023年第3期919-931,共13页Acta Sedimentologica Sinica

基　　金：中海油十四五重大科技项目(KJGG20220902)。

摘　　要：通过综合分析地震及钻井资料,阐述了Doseo盆地的区域地质特征、盆地结构及沉积体系特征,确定了Doseo盆地幕式裂谷演化过程及反转改造特征。重点分析了Doseo盆地自早白垩世以来的沉积充填演化特征,认为盆地经历了早白垩世Neocomian-Barremian期的张性断陷、Aptian-Albian期的走滑—拉分断陷及晚白垩世—新近纪的广覆式坳陷三个发育阶段,形成了明显的下部断陷、上部广覆式坳陷的双层沉积充填结构,但盆地以早白垩世的张性及走滑—拉分断陷沉积充填为主,形成了广泛分布的湖相烃源岩及水下扇、三角洲前缘沉积储层,是盆地的主要勘探目标。Doseo盆地湖相沉积地层主要发育在早白垩世的张性及走滑—拉分断陷阶段,而且是一个快速湖泛过程,广泛发育退覆式三角洲沉积。早白垩世晚期在北部撒哈拉地台挤压作用下湖盆快速抬升消亡,晚白垩世—新近纪充填了河流相的粗碎屑沉积,在断陷活动中盆地缺乏旋回性湖相地层的发育过程。Doseo盆地下白垩统整体表现为“北部水下扇”、“南部短轴浅水三角洲”及“东北部长轴深水三角洲”的沉积体系分布格局。在构造—沉积作用的共同控制下,Doseo盆地陡坡带近岸水下扇及缓坡带三角前缘发育较好的储盖组合,是油气勘探较有利的沉积相带,已经发现了多个油气藏。同时盆地后期的构造反转也为陡坡带水下扇砂体及中部湖底扇沉积等岩性圈闭目标成藏提供了机会,是盆地主要的新勘探领域。Based on the comprehensive analysis of seismic and well data,the regional geological characteristics,basin structure,and sedimentary system characteristics of Doseo Basin are analyzed in detail,and its episodic rift evolution process and inversion transformation characteristics are determined.This paper focuses on the sedimentary filling evolution characteristics of Doseo Basin since the Early Cretaceous.The basin experienced the sedimentary filling of the Neocomian-Barremian tension rift in the Early Cretaceous,strike slip-pull rift in the Aptian-Albian,and extensive depression in the Late Cretaceous-Neogene,forming a double-layer sedimentary filling structure with a lower fault depression and upper extensive depression,However,the basin was mainly filled with extensional and strike slip-pull apart depression deposits in the Early Cretaceous,forming widely distributed lacustrine source rocks and underwater fan and delta front reservoirs,becoming the main exploration target layers of the basin.The lacustrine layers in the Doseo Basin are mainly developed in the Early Cretaceous extensional and strike slip-pull apart stage,and it is a rapid lake flooding process,with extensive development of retrogressive delta deposits.In the late Early Cretaceous,it uplifted and disappeared rapidly under the compression of the northern Sahara platform.In the Late Cretaceous-Neogene,it filled with coarse clastic deposits of fluvial facies and lacked the development process of cyclic lacustrine strata in the basin formatting activity.The Lower Cretaceous in the basin is characterized by the depositional system distribution pattern of “north underwater fan”,“south short axis shallow water delta”,and “northeast long axis deep water delta”.The characteristics of this evolution and development determine that the steep slope belt developed in the Lower Cretaceous of the Doseo Basin has a good reservoir-cap assemblage near the source subaqueous fan and the triangular front of the gentle slope belt,which is a favorable sedime

关 键 词：白垩纪 深水三角洲 Doseo盆地 中非裂谷 近源水下扇 退覆三角洲 断陷期 

分 类 号：P512.2[天文地球—地质学]