摘要
Termit盆地是西非裂谷系中典型的海相沉积盆地,海陆过渡相沉积特征对于盆地烃源岩、储层、盖层及油气生成、聚集的影响巨大。Moul凹陷白垩系Yogou组是Termit盆地海相油气勘探的典型成功实例。受构造沉降与海平面变化控制,Moul凹陷白垩系Yogou组发育曲流河三角洲、辫状河三角洲、远岸水下扇、混积陆棚及滨浅海等5种沉积相类型;凹陷东部发育辫状河三角洲—远岸水下扇沉积体系,凹陷西部发育曲流河三角洲—混积陆棚沉积体系,凹陷中心则以浅海和远岸水下扇沉积体系为主;Yogou组沉积相序演化垂向呈"浅海—远岸水下扇—三角洲"进积序列叠加的特点,平面具有"盆缘三角洲—盆内重力流—混积陆棚"多相匹配的特征,使烃源岩与储层呈"纵向叠置相邻、平面广泛分布"的分布格局,形成了多套"三明治"式优质生储盖组合,为油气成藏奠定坚实的基础;Yogou斜坡、Koulele帚状带及Trakes斜坡油气运聚条件优越,保存条件良好,是勘探重点区带;YSQ1、YSQ2高位域及YSQ3低位域生储盖组合条件好,是主要目的层段。在地质认识基础上,优化井位部署,多口井获工业油流,有力推动了盆地油气勘探的进程。
The Termit Basin is a typical marine sedimentary basin of the western African rift system.Marine-continental transition facies sedimentary characteristics have exerted strong impacts on the source-reservoir-cap rocks,hydrocarbon generation,accumulation and distribution of hydrocarbon reservoirs in marine sedimentary basins.The Yogou Formation in Moul Sag is a typical successful example of oil-gas exploration of marine sedimentary basins.Affected by the tectonic subsidence and sea-level change,there are 5types of sedimentary facies developed in the Yogou Formation,including meandering river delta,braided river delta,far subaqueous fan,hybrid carbonate shelf and offshore.There mainly developed braided river delta and far subaqueous fan in the east,meandering river delta and hybrid carbonate shelf in the west,and neritic and far subaqueous fan in the center of the sag.The sedimentary facies sequence are characterized by＂neritic-far subaqueous fan-delta＂multi-progressive sequence in vertical evolution,＂delta in basin margin-gravity flow in deep water-hybrid carbonate shelf＂multi-facies proper match in plane,high quality source rocks and wide spread reservoirs contact closely vertically,material reservoir forming multiple sets of sandwich-like source-reservoir-cap assemblages,providing foundations for oil and gas accumulation;Yogou,Trakes slope and Koulele fastificted area inherited positive structural zone with the advantage of hydrocarbon migration,accumulation and preservation,which is the next exploration target;YSQ1-YSQ2 HST and YSQ3 LST source-reservoir-seal assemblage in excellent condition,is the target strata exploration.On the basis of these understanding,well placement schemes were optimized,industrial oil flow of Yogou Formation were received in many wells,which has greatly promoted the oil and gas exploration in Termit Basin
出处
《天然气地球科学》
EI
CAS
CSCD
北大核心
2016年第7期1153-1163,共11页
Natural Gas Geoscience
基金
国家科技重大专项"海外重点裂谷盆地油气成藏规律及目标优选"(编号:2008ZX05029-001)资助
关键词
海陆过渡相
沉积特征
生储盖组合
油气勘探
Moul凹陷
Marine-continental transition
Sedimentary characteristics
Source-reservoir-cap rocks
Oil-gas exploration
Moul Sag
