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高校地质学报 ›› 2019, Vol. 25 ›› Issue (6): 813-.DOI: 10.16108/j.issn1006-7493.2019087

• 烃源岩地球化学专栏 • 上一篇    下一篇

东濮凹陷古近系成烃生物特征及其生烃潜力研究

张云献,胥畅   

  1. 1. 中国石化中原油田分公司,濮阳 457001;
    2. 南京大学地球科学与工程学院,南京 210023
  • 收稿日期:2019-10-12 修回日期:2019-11-12 出版日期:2019-12-20 发布日期:2020-01-06

Characteristics and Generation Potential of Paleogene Hydrocarbon Organisms in the Dongpu Sag

ZHANG Yunxian,XU Chang   

  1. 1. Zhongyuan Oilfield Branch Company, SINOPEC, Puyang 457001, China;
    2. School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China
  • Received:2019-10-12 Revised:2019-11-12 Online:2019-12-20 Published:2020-01-06

摘要: 通过光学显微镜和扫描电镜对东濮凹陷古近系沙河街组烃源岩的成烃生物进行了研究。结果显示,研究区沙河街组的成烃生物发育,种类繁多,主要包括沟鞭藻、绿藻、蓝藻、颗石藻等。发育于东濮凹陷北部咸水区的成烃生物优势组合是沟鞭藻、蓝藻、颗石藻,且三者均可形成藻纹层;南部淡水区的成烃生物优势组合是绿藻及高等植物,发育于块状泥岩之中。对分别取于咸水区和淡水区的两个样品进行了热模拟实验,实验结果显示,北部咸水区的蓝藻和颗石藻的生烃潜力高,生油门限低,在低熟阶段即可大量生油,生成低熟油的控制因素是蓝藻的勃发;沟鞭藻和绿藻类的生油门限较高,其中沟鞭藻由于能大量勃发,是重要的成烃生物;南部淡水区的绿藻类较沟鞭藻类生烃潜力更低,生油门限更高。

关键词: 沟鞭藻, 蓝藻, 颗石藻, 热模拟

Abstract: The hydrocarbon-generating organisms in the source rocks of the Paleogene Shahejie Formation in the Dongpu sag were studied by optical microscopy and SEM. Results show that such organisms are well developed and various in types, including dinoflagellate, green algae, cyanobacteria and coccolithophores. Major combination of hydrocarbon-generating organisms developed in saline water area of the northern Dongpu Sag include dinoflagellate, cyanobacteria and coccolithophores, all of which can form algal laminae. In contrast, major combination of hydrocarbon-generating orgnisms developed in freshwater area of the southern Dongpu Sag include green algae and higher plants, which are developed in massive mudstone. Thermal simulation experiments were conducted on
two samples taken from saltwater and freshwater areas, respectively. It is showed that cyanobacteria and coccolithophores in saline water area have high hydrocarbon generation potential and low oil generation threshold, and can generate large amount of oil at low maturity stage, and the controlling factor of producing low maturity oil is cyanobacteria. The oil generation threshold of dinoflagellates and green algae is higher, among which dinoflagellates are important hydrocarbon generation organisms because of their large amount of biomass. Algae in the freshwater area have lower hydrocarbon generation potential and higher oil generation threshold than dinoflagellates.

Key words: dinoflagellates, cyanobacteria, coccolithophores, thermal simulation