摘要
乌干达Albert地堑位于东非裂谷西支北段,是晚中新世开始发育的陆内裂谷盆地。盆地油气资源丰富,中新—上新统砂岩是盆地的主要储层。综合运用录井、测井、岩心、孢藻和地震等资料分析认为,该时期气候温湿,湖平面振荡式上升;盆地物源体系复杂,发育Victoria Nile、Albert Nile和Kafu等多条主水系;盆地构造分带差异明显,由北至南依次发育缓坡带、中部断阶带、南部陡断带、断阶带和高角度斜坡带。北部缓坡带发育沿盆地长轴方向的正常三角洲;中部断阶带、南部陡断带及南部断阶带发育一系列垂直于盆地轴向的扇三角洲及湖底扇;高角度斜坡带发育沿盆地长轴方向的扇三角洲及近岸水下扇。沉积体系的类型及展布特征与物源体系、构造分带、湖平面升降和气候特征密切相关。综合分析认为盆地北部区域、东部边界断层下降盘及盆地南部是良好的储盖组合发育区。
The Albert Graben,Uganda,located in the northern part of the west branch of The East African Rift Valley,is an intra-continental rift basin developed in Late Miocene.The basin is rich in oil and gas,and the Miocene-Pliocene sandstone is the main reservoir.Based on well logs,cores and palynology data,the authors conclude that the climate was warm and humid there in Miocene to Pliocene,and the lake level rose with oscillation.The source system of the graben is complex,The Victoria Nile,Albert Nile and Kafu Rivers are the main streams.The graben,from north to south,might be divided into northern gentle slope belt,middle fault step belt,southern steep fault belt,southern fault step belt and steep slope belt.The northern gentle slope belt is filled with fluvial-deltaic system distributed along the graben axis.The middle fault step belt,southern Steep fault belt and southern fault step belt are featured by several fan delta systems distributed perpendicular to the long axis of the graben,while the southern steep slope belt is deposited with fan delta and sub-lacustrine fan deposits distributed along the graben axis.The sedimentation of the graben is controlled by source systems,tectonic belts,lake level fluctuation and climate changes.Based on above research,it is concluded that the northern part of the graben,the eastern boundary fault downthrow area and the southern part of the graben,which have good reservoir and seal assemblage,are the most favorable area for exploration.
出处
《海洋地质前沿》
2016年第2期29-37,共9页
Marine Geology Frontiers
