石油与天然气地质 ›› 2022, Vol. 43 ›› Issue (4): 777-791.doi: 10.11743/ogg20220404

• 油气地质 • 上一篇    下一篇

珠江口盆地惠州26洼“源-汇-聚”特征与惠州26-6大油气田发现启示

施和生1(), 高阳东2, 刘军2, 朱俊章2, 龙祖烈2, 史玉玲2   

  1. 1.中海石油(中国)有限公司 勘探部,北京 100010
    2.中海石油(中国)有限公司 深圳分公司,广东 深圳 518054
  • 收稿日期:2022-01-24 修回日期:2022-05-15 出版日期:2022-07-14 发布日期:2022-07-14
  • 第一作者简介:施和生(1962—),男,博士、教授级高级工程师,油气勘探。E?mail: shihsh@cnooc.com.cn
  • 基金项目:
    国家科技重大专项(2016ZX05024)

Characteristics of hydrocarbon source-migration-accumulation in Huizhou 26 Sag and implications of the major Huizhou 26-6 discovery in Pearl River Mouth Basin

Hesheng Shi1(), Yangdong Gao2, Jun Liu2, Junzhang Zhu2, Zulie Long2, Yuling Shi2   

  1. 1.Exploration Department,CNOOC,Beijing 100010,China
    2.Shenzhen Branch,CNOOC,Shenzhen,Guangzhou 518054,China
  • Received:2022-01-24 Revised:2022-05-15 Online:2022-07-14 Published:2022-07-14

摘要:

珠江口盆地发现的油气资源主要集中在拗陷期沉积的中新统-渐新统,在断陷期沉积的始新统中找到的油气仅占已发现油气资源的8 %,而在中生代古潜山领域尚未获得商业性油气发现。富烃洼陷是否有大量的油气仍保存在中-深层的断陷层系内,古近系和中生代古潜山(“双古”)地层油气运-汇通道是否有效发育,成藏动力的强弱,以及圈闭和储-盖组合是否发育等是古近系和中生代古潜山领域勘探面临的主要问题。基于“源-汇-聚”评价思想,通过对珠江口盆地惠州26洼的源(烃源岩类型与质量、热成熟演化史与生排烃史、油气资源类型与规模)、汇(运-汇单元、运-汇方向、输导通道、汇聚强度)、聚(二级构造带与圈闭、储-盖组合、充注强度、保存条件)等静态和动态成藏要素相结合进行深入研究,揭示了惠州26洼古近系和中生代古潜山领域的源-汇-聚特征,提出了“油型烃源岩晚期加快熟化、先油后气、断-压双控、源-储对接强势供烃、立体运聚”动态成藏模式,推动了惠州26-6构造古近系和中生代古潜山新领域勘探获得重大突破。

关键词: 动态成藏, 源-汇-聚评价, 中生代古潜山, 古近系, 惠州26-6油气田, 惠州26洼, 珠江口盆地

Abstract:

In the Pearl River Mouth Basin, a majority of hydrocarbons were discovered in the Miocene-Oligocene reservoir rocks deposited during the depression stage, while only 8 % of the discovered hydrocarbons were found in the Eocene reservoir rocks formed during the rifting stage, and no commercial discoveries have been made in the Mesozoic buried hills. The main problems in exploration for the Paleogene reservoir rocks and Mesozoic buried hills include whether there are a quantity of hydrocarbons still preserved in the middle-to-deep downfaulted reservoir rocks of hydrocarbon-rich sags, whether the hydrocarbon migration pathways are effectively developed in the Paleogene reservoir rocks and Mesozoic buried hills, as well as whether the hydrocarbon accumulation dynamics, traps and reservoir-seal assemblages are well developed. In line with the assessment theory of “source-migration-accumulation”, the study discusses the static and dynamic elements of the hydrocarbon accumulation system in Huizhou 26 Sag, Pearl River Mouth Basin, including the hydrocarbon source in terms of types and quality of source rocks, thermal evolution and hydrocarbon generation-expulsion history, and types and scale of hydrocarbon resources, the hydrocarbon migration in terms of migration unit and direction, migration pathway, confluence intensity, as well as the hydrocarbon accumulation in terms of secondary structural belt and trap, reservoir-seal assemblage, charging intensity and preservation condition. In conclusion, the study reveals the characteristics of source-migration-accumulation for the Paleogene reservoir rocks and Mesozoic buried hills in Huizhou 26 Sag, sets up a dynamic accumulation model featuring “accelerated maturation of oil-prone source rocks at later stages, generation of oil at first followed by gas, joint control of fault and overpressure, strong hydrocarbon supply by source-reservoir juxtaposition, and 3D migration and accumulation”. Major breakthrough has been made thereby in the exploration for the Paleogene reservoirs and Mesozoic buried hills in Huizhou 26-6 structure.

Key words: dynamic accumulation, source-migration-accumulation assessment, Mesozoic buried hill, Paleogene, Huizhou 26-6 oil/gas field, Huizhou 26 Sag, Pearl River Mouth Basin

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