特种油气藏 ›› 2022, Vol. 29 ›› Issue (1): 15-22.DOI: 10.3969/j.issn.1006-6535.2022.01.003

• 地质勘探 • 上一篇    下一篇

准噶尔盆地沙湾凹陷周缘上古生界天然气地球化学特征及成因研究

李二庭1,2, 靳军1,2, 廖健德1,2, 周波1,2, 马万云1,2, 王海静1,2   

  1. 1.中国石油新疆砾岩油藏实验室,新疆 克拉玛依 834000;
    2.中国石油新疆油田分公司,新疆 克拉玛依 834000
  • 收稿日期:2020-09-25 修回日期:2021-11-20 出版日期:2022-02-25 发布日期:2023-01-10
  • 作者简介:李二庭(1988—),男,高级工程师,2010年毕业于中山大学应用化学专业,2015年毕业于中国科学院广州地球化学研究所地球化学专业,获博士学位,出版著作2部,现从事油气勘探工作。
  • 基金资助:
    国家油气重大专项“准噶尔前陆冲断带油气成藏、关键勘探技术及新领域目标优选”(2016ZX05003-005)

Study on Geochemical Characteristics and Genesis of Upper Paleozoic Natural Gas in the Perimeter of Shawan Sag, Junggar Basin

Li Erting1,2, Jin Jun1,2, Liao Jiande1,2, Zhou Bo1,2, Ma Wanyun1,2, Wang Haijing1,2   

  1. 1. PetroChina Xinjiang Conglomerate Reservoir Laboratory, Karamay, Xinjiang 834000, China;
    2. PetroChina Xinjiang Oilfield Company, Karamay, Xinjiang 834000, China
  • Received:2020-09-25 Revised:2021-11-20 Online:2022-02-25 Published:2023-01-10

摘要: 针对准噶尔盆地沙湾凹陷周缘上古生界天然气成因与来源认识不清的问题,运用烃源岩热解气模拟实验技术,根据热解气碳同位素分布,结合天然气组分、碳同位素、轻烃组成及伴生原油地球化学特征,揭示了沙湾凹陷周缘上古生界天然气成因与来源。研究结果表明:研究区天然气具有6种成因类型,Ⅰ类天然气来源于佳木河组烃源岩,δ13C2值大于-26.0‰;Ⅱ类天然气为生物气,具有偏负δ13C1值和极高的干燥系数;Ⅲ类天然气来源于佳木河组烃源岩与下乌尔禾组烃源岩混合,干燥系数大于0.95,δ13C2在-26.0‰左右;Ⅳ类天然气来源于下乌尔禾组烃源岩,δ13C2值为-27.5‰~-26.9‰;Ⅴ类天然气主要为下乌尔禾组烃源岩与风城组烃源岩混源,其中,δ13C2值不小于-29.0‰的天然气以下乌尔禾组来源为主,δ13C2值小于-29.0‰的天然气以风城组来源为主;Ⅵ类天然气来源于风城组烃源岩,δ13C2值小于-31.0‰。研究区存在二叠系佳木河组、下乌尔禾组腐殖型和风城组腐泥型3套有效气源岩。研究成果解决了沙湾凹陷周缘上古生界气源问题,可为研究区天然气勘探和成藏研究提供依据。

关键词: 天然气, 热模拟, 上古生界, 沙湾凹陷, 准噶尔盆地

Abstract: To address the problem of poor understanding of the genesis and source of the Upper Paleozoic natural gas in the perimeter of Shawan Sag, Junggar Basin, the simulation and experiment of source rock pyrolysis gas were conducted to work out the genesis and sources of the Upper Paleozoic natural gas in the perimeter of Shawan Sag based on the carbon isotope distribution of pyrolysis gas, as well as the natural gas components, carbon isotopes, light hydrocarbon composition and geochemical characteristics of associated crude oil. The results showed that there were six types of gas genesis in the study area. Type Ⅰ natural gas was derived from the source rocks of Jiamuhe Formation with a δ13C2 value greater than -26.0‰; Type Ⅱ natural gas was biogas with negative δ13C1 value and extremely high aridity coefficient; Type Ⅲ natural gas was derived from the source rocks of Jiamuhe Formation and the source rocks of Lower Wuerhe Formation, with an aridity coefficient of greater than 0.95, and δ13C2 value of about -26.0‰; Type Ⅳ natural gas was derived from the source rocks of Lower Wuerhe Formation, with δ13C2 value ranging from -27.5‰ to -26.9‰; Type Ⅴ natural gas mainly originated from the source rocks of Lower Wuerhe Formation and Fengcheng Formation, among which, the natural gas with a δ13C2 value of not less than -29.0‰ was from Lower Wuerhe Formation and the natural gas with a δ13C2 value of less than -29.0‰ was mainly from Fengcheng Formation; Type Ⅵ natural gas originated from the source rocks of Fengcheng Formation with a δ13C2 value of less than -31.0‰. There are three types of effective gas source rocks in the study area, including humic source rocks of Permian Jiamuhe Formation, humic source rocks of Lower Wuerhe Formation and sapropelic source rocks of Fengcheng Formation. The study results give a answer to the gas source problem of the Upper Paleozoic in the perimeter of Shawan Sag, and provide a basis for the study on natural gas exploration and reservoir accumulation in the study area.

Key words: natural gas, thermal simulation, Upper Paleozoic, Shawan Sag, Junggar Basin

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