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现代地质 ›› 2015, Vol. 29 ›› Issue (1): 109-118.

• 石油地质学 • 上一篇    下一篇

澳大利亚Bonaparte盆地大陆边缘裂陷期局限海相页岩发育特征与模式

侯宇光1,何生1,杨香华1,朱光辉2,段威1,许晓明2   

  1. (1.中国地质大学 构造与油气资源教育部重点实验室,湖北 武汉430074;
    2.中海石油(中国)有限公司 北京研究中心,北京100027)
  • 出版日期:2015-01-29 发布日期:2015-04-21
  • 作者简介:侯宇光,男,副教授,1979年出生,石油地质专业,主要从事油气成藏、非常规油气地质方面的教学和研究工作。Email:sporthyg@126.com。
  • 基金资助:

    国家油气重大专项(2008ZX05030-02);国家自然科学基金项目(41302111);高等学校学科创新引智计划资助项目(B14031);中央高校基本科研业务费专项资金资助项目(CUGL110247);构造与油气资源教育部重点实验室基金项目(TPR-2013-19)。

Characteristics and Development Model of Restricted Sea Shale at Continental Margin Rifting Stage in Bonaparte Basin, Australia

HOU Yu-guang1, HE Sheng1, YANG Xiang-hua1, ZHU Guang-hui2, DUAN Wei1, XU Xiao-ming2   

  1. (1.Key Laboratory of Tectonics and Petroleum Resources (China University of Geosciences), Ministry of Education, Wuhan, Hubei430074, China;
    2.Beijing Research Center, CNOOC Ltd, Beijing100027, China)
  • Online:2015-01-29 Published:2015-04-21

摘要:

发育于大陆边缘裂陷阶段以局限海相为主要沉积环境的富含浮游藻类泥页岩可能是Bonaparte盆地潜在的重要“油”源岩。从构造地质背景、沉积充填特征以及有机地球化学特征等多方面进行综合分析表明,局限海相页岩形成于大陆边缘裂陷阶段的衰减期,盆地基底的差异裂陷活动为页岩的形成提供了高可容纳空间和欠补偿的沉积环境,同时,“小隆大凹”的沉积格局更加有利于大规模相对稳定的半封闭的局限海沉积环境的形成和海相浮游藻类的繁盛。以扇三角洲和海底扇为主的物源体系带来大量“陆源”营养物质,同时,保持营养物质的供给与欠补偿条件的平衡。局限海相页岩主要形成于弱氧化、陆源物质供给较弱、局限海范围较大的沉积环境;岩性上以海相泥岩为主,陆源孢粉化石与沟鞭藻化石均较发育,或后者含量略高;沉积厚度适中、分布范围局限;有机质丰度相对较高,以混合型有机质为主,成熟度较低,气相色谱以前峰型为主,(nC21+nC22)/(nC28+nC29)和Pr/Ph比值相对较高,甾萜等生物标志化合物参数以低C19三环二萜和C24四环萜烷、高孕甾烷、高αααC27R/αααC29R为特征。

关键词: 地球化学特征, 发育模式, 局限海相页岩, 大陆边缘裂陷期, Bonaparte盆地, 澳大利亚

Abstract:

The argillutite with significant marine planktonic debris which mainly deposited in restricted sea during the continental margin rifting stage is likely the potential important oil source rock of the Bonaparte basin, north-western Australia. Comprehensive analyses on the tectonic geology settings, depositional filling characteristics and organic geochemistry characteristics showed that: The restricted sea shale developed during the decline rifting stage of the continental margin rifting stage in Bonaparte basin. Not only did the episodic rifting of the basin and differential subsidence of contemporaneous faults provide the high accommodation space and the undercompensation depositional environment, but also formed the depositional pattern of “big sag surrounding by little uplifts” which is more benefit for the development of relative-permanent semi-enclosed restricted sea and the propagation of marine planktonic algae. The provenance systems were consisted of the fan delta and the submarine fan, accompanying the significant terrigenous organic matter input to keep the balance of the organic matter supplying with the undercompensation depositional situation. The restricted sea shale deposited in slight oxidation marine depositional environment with large scale restricted sea and minor terrestrial organic matter input, and were mainly the margin mudstone with rich terrigenous organic matter and marine planktonic debris or the latter is higher. The sediment has a moderate thickness and restricted distribution. Geochemical characteristics show relatively high organic matter abundance, dominantly mixed kerogen type and low maturity. The gas chromatograms display front end biased distributions, and are characterized by relatively high (nC21+nC22)/(nC28+nC29) and Pr/Ph ratios. Biomarker fingerprints are characterized by low C19 tricyclic terpane and C24 tetracyclic terpane, high pregnane and C27/C29 regular steranes.

Key words: geochemistry characteristics, development model, restricted sea shale, continental margin rifting stage, Bonaparte basin, Australia

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