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现代地质 ›› 2021, Vol. 35 ›› Issue (04): 1078-1087.DOI: 10.19657/j.geoscience.1000-8527.2020.030

• 油气勘探与开发 • 上一篇    下一篇

南祁连盆地木里坳陷油气来源分析:基于DK-9孔岩心样品热模拟实验

唐世琪1(), 卢振权2(), 程斌3, 廖泽文3, 刘晖2, 王婷2, 范东稳2, 张富贵1   

  1. 1.中国地质科学院 地球物理地球化学勘查研究所,河北 廊坊 065000
    2.中国地质调查局 油气资源调查中心,北京 100083
    3.中国科学院广州地球化学研究所 有机地球化学国家重点实验室,广东 广州 510640
  • 收稿日期:2019-11-08 修回日期:2020-04-22 出版日期:2021-08-10 发布日期:2021-09-08
  • 通讯作者: 卢振权
  • 作者简介:卢振权,男,研究员,1972年出生,矿物学、岩石学、矿床学专业,从事天然气水合物地质地球化学勘查等研究。Email: luzhq@vip.sina.com
    唐世琪,女,硕士,1991年出生,石油地质专业,主要从事油气地球化学研究工作。Email: 642191779@qq.com
  • 基金资助:
    国家自然科学基金项目(41073040);中国地质调查局天然气水合物勘查与试采国家专项项目(GZHL20110310);中国地质调查局天然气水合物勘查与试采国家专项项目(GZHL20110311)

Source Analysis of Oil and Gas Indication in Muli Depression of South Qilian Basin:A Thermal Simulation Case Study of DK-9 Core

TANG Shiqi1(), LU Zhenquan2(), CHENG Bin3, LIAO Zewen3, LIU Hui2, WANG Ting2, FAN Dongwen2, ZHANG Fugui1   

  1. 1. Institute of Geophysical & Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang,Hebei 065000,China
    2. Oil and Gas Survey, China Geological Survey, Beijing 100083, China
    3. State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou,Guangdong 510640,China
  • Received:2019-11-08 Revised:2020-04-22 Online:2021-08-10 Published:2021-09-08
  • Contact: LU Zhenquan

摘要:

南祁连盆地木里坳陷部署的多个天然气水合物钻孔钻遇不同程度的水合物与油气显示伴生现象,指示该地区具有良好的油气勘探前景,有必要对已发现油气显示进行来源分析。由于水合物钻孔深度有限,针对DK-9孔4组油气显示样品,在开展现有烃源岩油源对比基础上,选取中侏罗统、上三叠统各5组代表性低熟烃源岩样品进行热模拟实验,模拟深部烃源岩生、排烃过程,将新生烃类再次与油气显示进行对比,进一步探究油气显示来源。结果显示,油气显示可分为两类(Ⅰ和Ⅱ),第Ⅰ类油气显示遭受生物降解作用,成熟度稍高,第Ⅱ类油气显示成熟度稍低;现有烃源岩主要分为三种类型(Ⅰ—Ⅲ),分别对应深度163.30~207.42 m、 207.42~348.50 m、357.90~586.50 m。结合常规油源对比、热模拟实验与地质条件分析,最终推测第Ⅰ类油气显示主要与第Ⅰ类烃源岩同源;第Ⅱ类油气显示主要与第Ⅱ类烃源岩同源,此外可能还有第Ⅲ类烃源岩或更深层烃源岩的贡献,即其母质来源既与中侏罗统烃源岩有关又与上三叠统烃源岩有关。

关键词: 油气显示, 来源, 热模拟, 木里坳陷, 南祁连盆地

Abstract:

Multiple gas hydrate boreholes in the Muli Depression (South Qilian Basin) have encountered varying coexistence of hydrates and oil-gas, indicating good potential for oil and gas exploration. It is thus necessary to perform source analysis on the discovered oil and gas indications. In this study, four groups of oil and gas samples from borehole DK-9 were studied. Due to the limited drilling depth, on the basis of oil source comparison of existing source rocks, thermal simulation was conducted on five representative lowly-mature source rocks (Middle Jurassic and Upper Triassic) to constrain the hydrocarbon generation process. The results were then compared with the oil and gas to further constrain their source. The results reveal that the oil and gas indications can be divided into two types: (Ⅰ) those with biodegradation and are slightly more mature, and (Ⅱ) those that are slightly less mature. The source rocks comprise mainly three types, corresponding to 163.30-207.42 m, 207.42-348.50 m, and 357.90-586.50 m depths, respectively. Considering also the conventional oil source comparison, the thermal simulation and the geological condition analysis, it is concluded that type I oil and gas is mainly homologous with type I source rocks. Type Ⅱ oil and gas may have had the same origin as type Ⅱ source rocks, and may also be contributed by type Ⅲ source rocks and/or deeper source rocks, i.e., its parent material is related to both the Middle Jurassic and the Upper Triassic source rocks.

Key words: oil and gas indication, source, thermal simulation, Muli Depression, South Qilian Basin

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