西非陆缘盆地中南段构造与沉积研究  

Review of Tectonic-sedimentary Features of the Central-south Section of West African Continental Margin Basins

作　　者：鲁宝亮[1,2] 王万银[1,2] 杜向东 黄兴文 郭允 纪晓琳[1,2] 冯旭亮[1,2] 

机构地区：[1]长安大学地质工程与测绘学院,陕西西安710054 [2]长安大学重磁方法技术研究所,陕西西安710054 [3]中海油研究总院,北京100027

出　　处：《海洋科学进展》2015年第3期414-428,共15页Advances in Marine Science

基　　金：国家科技重大专项--大陆边缘盆地地球物理勘探关键技术攻关与应用研究(2011ZX05030-004);中央高校基本科研业务费专项--南海东北部海区中生代残留盆地三维结构地球物理数据约束构建(310826151052)和重磁方法理论及应用研究(2014G3262010)

摘　　要：作为全球油气勘探的热点,西非陆缘盆地中南段已经获得了大量的油气发现,而且中国石油企业在该区域已有开发区块。巨厚的阿普特期盐岩将该区分为盐下陆相裂谷和盐上海相被动陆缘两套勘探层系,该套盐岩作为良好的盖层起到了保存油气的作用,但由于其遮蔽效应,导致了地震资料在盐下层成像品质差,造成了盐下层序研究程度低,裂谷主控断裂、裂谷规模及展布形态不清楚,严重制约了盐下油气勘探的进程。本文综述了国内外近年来关于西非陆缘盆地中南段构造演化、盐上和盐下层序构造、盐岩特征以及盆地构造的研究进展。目前针对盐下裂谷研究主要集中在陆区,海域研究程度低,现有的盆地构造单元划分是以盐上层序为主,并不适用于盐下油气勘探先进问题,建议加强该区基础地质与地球物理研究,开展与南美东部陆缘盆地盐下裂谷对比研究,提高盐下地震成像品质,重视地震-重磁联合研究,通过地质与地球物理综合研究,尽快查明盐下裂谷主控断裂、基底形态、隆坳格局等油气分布控制因素,为中国石油公司在该区油气战略选区及下步勘探部署提供依据。As a hotspot area of oil and gas exploration in the world,the central-south section of west African continental margin basins hold a large number of oil and gas which have been explored,where Chinese oil companies have several development blocks Thick Aptian salt rock,which is a notable feature in central-south section of continental margin in West Africa,were divided into the following two exploration sequences,continental rifting below salt and passive margin above salt,and the sequence strata sequence below salt has become an important exploration target.The Aptian salt plays a significant role in saving gas,and thereby it has lower image quality because of masking effect.Therefore,previous studies on subsalt rifts were very poor,and some key geological characteristics such as the major boundary faults（MBFs）and rifts morphological dimensions are unclear,which seriously hampered the process of subsalt oil and gas exploration.In this study,we reviewed the tectonic evolution,pre-/post-salt structures,evaporites and basin structures of the central-south section of West African continental marginal basins.The present studies on rifts were mainly focused on the land areas of the basins,and few studies paid attention to the sea areas.And,the basin tectonic units division was mainly based on the post-salt sequences,so the theory cannot apply to oil and gas exploration of pre-salt rifts.Thus we proposed that the study of basic geology and geophysics in the study area should be strengthened,the comparative study of the central-south section of west African continental margin basins and Brazilian subsalt eastern continental margin rift basins should be performed,and the quality of seismic imaging of subsalt should be improved.Through a comprehensive study of geology and geophysics,we can identify MBFs of subsalt rifts,basement form and distribution of uplifts and sags as soon as possible,and which will be an important basis for the next research work and strategic exploration planning.

关 键 词：西非 蒸发岩 裂谷构造 盐下成像 油气勘探 

分 类 号：TE121.3[石油与天然气工程—油气勘探]