特种油气藏 ›› 2025, Vol. 32 ›› Issue (6): 33-39.DOI: 10.3969/j.issn.1006-6535.2025.06.004

• 地质勘探 • 上一篇    下一篇

南加蓬盆地阿普特期不整合特征及对油气藏的控制作用

李海滨, 黄健良, 任艳   

  1. 中国海洋石油国际有限公司,北京 100028
  • 收稿日期:2025-01-06 修回日期:2025-09-12 出版日期:2025-12-25 发布日期:2025-12-31
  • 作者简介:李海滨(1980—),男,工程师,2004年毕业于大庆石油学院勘查技术与工程专业,2013年毕业于南京大学构造地质学专业,获博士学位,现主要从事油气综合地质研究工作。
  • 基金资助:
    中海油“十四五”重大科技项目“两岸一带重点区油气勘探评价关键技术” (KJGG2022-0902)

Aptian unconformity characteristics and their controlling role on petroleum reservoirs in the South Gabon Basin

LI Haibin, HUANG Jianliang, REN Yan   

  1. CNOOC International Limited,Beijing 100028,China
  • Received:2025-01-06 Revised:2025-09-12 Online:2025-12-25 Published:2025-12-31

摘要: 南大西洋中段两岸盆地在早白垩世阿普特期形成了区域分布的破裂不整合,为了研究其对油气成藏的控制作用,以西非南加蓬盆地为例,基于地震、钻井及油气藏分布资料,通过分析不整合的类型、结构及空间分布,研究其对油气运聚成藏的控制作用。研究表明,不整合上、下地层分别发育披覆背斜和潜伏剥蚀构造;纵向上具有双层结构,上部水进砂岩分布广、物性好、砂地比高、盐岩遮挡层封盖条件好,可以作为油气长距离运移的通道;下部半风化砂、泥岩侧向变化快,缺少厚层风化黏土岩盖层,难以成为有效的横向输导层;盆地内坳陷带发育构造-地层复合油气藏,中部隆起带主要发育披覆背斜油气藏,外坳陷带发育断层油气藏。该研究可对南大西洋两岸盆地油气勘探提供有益的借鉴。

关键词: 南加蓬盆地, 不整合, 输导体系, 披覆背斜, 复合油气藏

Abstract: During the Early Cretaceous Aptian,widespread regional unconformities formed along the mid-South Atlantic rift basins, acting as major hydrocarbon migration pathways.With the South Gabon Basin in West Africa as an example, using seismic, drilling, reservoir data analysis was made on the types, structures and spatial distribution of Aptian unconformities to study their control on petroleum accumulation.Results showed that above and below the unconformity,overlaying anticlines(thrust-related folds)and relict erosional structures developed,respectively.Vertically,a dual-layer structure existed:the upper layer consisted of widely distributed water-conducting sandstones with good properties,high sand fractions and effective sealing by overlying salt, serving as long-distance hydrocarbon migration pathways;the lower layer of semi-weathered sandstones and rapidly varying shales lacked thick weathered clay caps and could not act as effective lateral conduits.These characteristics led to formation of structural-stratigraphic composite petroleum traps in the interior sag,overthrust anticline traps in the central uplift,and faulted traps in the outer sag.This study provides valuable insight for exploration in South Atlantic rift basins.

Key words: South Gabon Basin, unconformity, migration pathway, overthrust anticline, composite petroleum trap

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