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现代地质 ›› 2021, Vol. 35 ›› Issue (02): 301-314.DOI: 10.19657/j.geoscience.1000-8527.2021.032

• 石油地质学 • 上一篇    下一篇

东濮凹陷盐湖相烃源岩有机硫同位素分布特征及其地球化学意义

柯昌炜1,2(), 李素梅1,2(), 张洪安3, 徐田武3, 张云献3, 曾凡纲4, 张树海1, 张韩静1   

  1. 1.中国石油大学(北京) 油气资源与探测国家重点实验室,北京 102249
    2.中国石油大学(北京) 地球科学学院,北京 102249
    3.中国石化中原油田分公司,河南 濮阳 457001
    4.中国人民大学 环境学院,北京 100872
  • 收稿日期:2020-09-23 修回日期:2020-12-15 出版日期:2021-04-25 发布日期:2021-05-25
  • 通讯作者: 李素梅
  • 作者简介:李素梅,女,研究员,1968年出生,有机地球化学专业,主要从事油气地质地球化学研究工作。Email: smli@cup.edu.cn
    柯昌炜,男,博士研究生,1992年出生,地质学专业,主要从事油气地质地球化学研究工作。Email: kechangwei061@163.com
  • 基金资助:
    国家自然科学基金项目(41673055);国家自然科学基金项目(42073064);国家科技重大专项(2016ZX05006-004)

Distribution Characteristics and Geochemical Significances of the Compound Specific Sulfur Isotope of Saline Lacustrine Source Rocks from the North Dongpu Depression, Bohai Bay Basin

KE Changwei1,2(), LI Sumei1,2(), ZHANG Hongan3, XU Tianwu3, ZHANG Yunxian3, ZENG Fangang4, ZHANG Shuhai1, ZHANG Hanjing1   

  1. 1. State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing 102249,China
    2. College of Geosciences,China University of Petroleum,Beijing 102249,China
    3. SINOPEC Zhongyuan Oilfield Company,Puyang,Henan 457001,China
    4. School of Environment & Natural Resources, Renmin University of China,Beijing 100872,China
  • Received:2020-09-23 Revised:2020-12-15 Online:2021-04-25 Published:2021-05-25
  • Contact: LI Sumei

摘要:

盐湖相烃源岩单体烃硫同位素分布特征和影响因素研究薄弱。采用气相色谱-电感耦合等离子体质谱,结合色谱/质谱、微量元素以及碳氧同位素技术,对东濮凹陷北部盐湖相烃源岩进行了分析。结果表明,不同单体含硫化合物的δ34S值有较大差异,以δ34S=25.00‰为界,将烃源岩分成了两类,第一类:δ34S>25.00‰,主要为卫城地区的烃源岩,总体具有单体烃硫同位素随分子量、烷基化程度增加而降低的特征;第二类:δ34S<25.00‰,主要为文留地区的烃源岩,单体烃硫同位素变化特征与卫城烃源岩相反。观察到二苯并噻吩的硫同位素与成熟度相关参数——饱和烃含量、三环萜烷/五环萜烷等有明显的正相关性、与“非烃+沥青质”含量有明显的负相关性,反映成熟度的控制作用,随成熟度增加,硫同位素有变重的趋势;观察到硫同位素与沉积环境相关参数伽马蜡烷/C31藿烷、C35/C34藿烷有明显的正相关性,与方解石、黏土矿物等含量和微量元素比值有很好的线性关系,反映原始沉积环境的控制作用,强还原、封闭的蒸发环境有助于有机质的硫化作用,从而使硫同位素变重。概括而言,烃源岩单体烃硫同位素有重要的沉积环境与成熟度指示意义,具有油—岩对比、成因类型划分的应用潜能。

关键词: 东濮凹陷, 盐湖相, 有机硫同位素, 微量元素, 沉积环境

Abstract:

The researches about compound specific sulfur isotopes of saline lacustrine source rocks are rare. Using the technology of gas chromatography with multicollector inductively coupled plasma mass spectrometry (GC-MC-ICP MS), combined with gas chromatography/mass spectrometry (GC/MS), carbon and oxygen isotopic and trace elements to analyze the source rocks (oil sands)from saline lacustrine northern of Dongpu Depression. The analysis results show that the sulfur isotopic values of individual hydrocarbon in source rocks (oil sands) are small, but the δ34S values of different sulfur compounds are quite different (5.16‰ to 44.73‰). Boundary with δ34S=25.00‰ the source rocks (and oil sands) can be divided into two categories, the first type with δ34S>25.00‰ is mainly Weicheng source rock characterized by the sulfur isotope of individual hydrocarbon decreases with the increase of methyl. And the δ34S<25.00‰ is the second type,which characteristics are opposite to Weicheng source rocks. The sulfur isotopes of dibenzothiophenes have obvious positive correlation with the content of saturated hydrocarbon, tricyclic terpane/pentacyclic terpane, and negative correlation with content of “nonhydrocarbon+asphaltene”. The sulfur isotopes of hydrocarbons have obvious positive correlation with gammacerane/C31hopane and C35/C34hopanes, excellent correlation with contents of minerals and ratios of trace elements, indicating that the isotopes of organic sulfur compounds in the closed evaporation environment becomes heavier, and the values in the open terrestrial input environment becomes lighter. The analysis shows that the sulfur isotopes of individual hydrocarbon are significantly controlled by the original sedimentary environment of source rock. Strong reduction and closed evaporation environment are conducive to the sulfuration of organic matter, which makes the sulfur isotope heavier. The sulfur isotopes are also affected by maturity, while the sulfur isotope tends to become heavier with the increase of maturity. Generally speaking, isotopes of organic sulfur compounds have important significance of indicating sedimentary environment and maturity, and the potential of oil-oil and oil-rock correlation.

Key words: Dongpu depression, saline lacustrine, isotopes of organic sulfur compounds, trace elements, sedimentary environment

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