石油与天然气地质 ›› 2022, Vol. 43 ›› Issue (1): 161-174.doi: 10.11743/ogg20220113

• 油气地质 • 上一篇    下一篇

准噶尔盆地西北缘天然气成因来源及勘探潜力

龚德瑜1(), 赵长永2, 何文军3, 赵龙3, 孔玉梅4, 马丽亚1, 王瑞菊1, 吴卫安1   

  1. 1.中国石油 勘探开发研究院, 北京 100083
    2.中国石油 新疆油田公司勘探事业部, 新疆 克拉玛依, 834000
    3.中国石油 新疆油田公司 勘探开发研究院, 新疆 克拉玛依 834000
    4.河北省煤田地质局物测地质队, 河北 邢台 054000
  • 收稿日期:2021-08-13 修回日期:2021-12-12 出版日期:2022-02-01 发布日期:2022-01-28
  • 第一作者简介:龚德瑜(1983—),男,高级工程师,油气地质与地球化学。E?mail: deyugong@petrochina.com.cn
  • 基金项目:
    国家自然科学基金项目(41802177);中国石油前瞻性基础性战略性技术攻关项目(2021DJ0206)

Genetic types and exploration potential of natural gas at northwestern margin of Junggar Basin

Deyu Gong1(), Changyong Zhao2, Wenjun He3, Long Zhao3, Yumei Kong4, Liya Ma1, Ruiju Wang1, Wei’an Wu1   

  1. 1.Research Institute of Petroleum Exploration & Development,PetroChina,Beijing 100083,China
    2.Exploration Department of Xinjiang Oilfield Company,PetroChina,Karamay,Xinjiang 834000,China
    3.Petroleum Exploration and Development Research Institute of Xinjiang Oilfield Company,PetroChina,Karamay,Xinjiang 834000,China
    4.Geophysical and Geological Division,Hebei Coalfield Geological Bureau,Xingtai,Hebei 054000,China
  • Received:2021-08-13 Revised:2021-12-12 Online:2022-02-01 Published:2022-01-28

摘要:

准噶尔盆地是中国陆上四大含油气盆地之一,但天然气勘探进展缓慢,已有发现主要集中在盆地的东部和南部。基于天然气的组分和稳定碳同位素组成,在准噶尔盆地西北缘发现了4种类型的天然气。第Ⅰ类天然气主要来自下二叠统风城组湖相烃源岩,可进一步细分为ⅠA(主要来自沙湾凹陷)和ⅠB(主要来自玛湖凹陷)两个亚类。第Ⅱ类天然气为沙湾凹陷深部石炭系和下二叠统佳木河组高-过成熟腐殖型烃源岩生成的煤型气。第Ⅲ类天然气为第Ⅰ和第Ⅱ类天然气的混合气。第Ⅳ类天然气为油藏破坏后发生生物降解作用而形成的次生生物成因气。白垩纪,沙湾凹陷风城组、佳木河组和石炭系烃源岩生成的大量高成熟煤型气和油型气沿断裂和不整合面组成的输导体系运移至构造高部位成藏,而玛湖凹陷风城组烃源岩主体仍处在生油高峰,生成少量低熟油型气在凹陷内及边缘聚集。上述发现证实了准噶尔盆地西部上古生界发育石炭系(含佳木河组)和风城组两套规模有效气源岩,揭示了新的天然气勘探领域。研究成果提供了一个复杂地质条件下开展气-源对比和成藏过程恢复的典型案例,同时也深化了对准噶尔盆地天然气勘探潜力的认识。

关键词: 碳同位素, 成因来源, 勘探潜力, 天然气, 准噶尔盆地

Abstract:

Although the Junggar Basin is one of the four major onshore petroliferous basins in China, the progress of natural gas exploration is poor with major discoveries confined to the eastern and southern parts of the basin. Based on gas composition and stable carbon isotopes, we find four types of natural gas at the northwestern margin of Junggar Basin. TypeⅠgas is primarily generated from the lacustrine source rocks of the Lower Permian Fengcheng Formation, and can be further subdivided into TypeⅠA (mainly derived from Shawai Sag) andⅠB (mainly from Mahu Sag). Type Ⅱgas is mainly of coaliferous gas derived from the Carboniferous and Lower Permian Jiamuhe humic source rocks of high to over-mature type in the Shawan Sag. Type Ⅲ gas is a mixture of TypeⅠandⅡ. Type Ⅳ gas is of secondary biogenic gas with oil biodegradation under reservoir destruction. During the Cretaceous, a mass of coaliferous and petroliferous gases were derived from the Fengcheng, Jiamuhe and Carboniferous source rocks in the Shawan Sag, which then migrated to higher parts of the structure along the carrier system composed of faults and unconformities; while the Fengcheng source rocks in the sag was at oil generation peak during which only a small amount of petroliferous gas of low maturity could be generated and accumulate within or over margins of the sag. In this study, it is confirmed that two suites of effective gas source rocks of large scale were developed in the Upper Paleozoic, west of Junggar Basin, that is, the Carboniferous (including Jiamuhe Formation) and Fengcheng Formation source rocks, serving to shed lights on a new field of natural gas exploration. In all, the study is of a typical case to show gas-source correlation under complex geological conditions and hydrocarbon accumulation restoration, and also deepens the understanding of the exploration potential of natural gas in the Junggar Basin.

Key words: carbon isotope, genesis and origin, exploration potential, natural gas, Junggar Basin

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