新疆石油地质 ›› 2022, Vol. 43 ›› Issue (6): 724-732.doi: 10.7657/XJPG20220610

• 油气勘探 • 上一篇    下一篇

玛湖凹陷玛页1井风城组富硅页岩成因及其油气意义

雷海艳(), 齐婧, 周妮, 陈俊, 孟颖, 张锡新, 陈锐兵   

  1. 1.新疆页岩油勘探开发重点实验室,新疆 克拉玛依 834000
    2.中国石油 新疆油田分公司 实验检测研究院,新疆 克拉玛依 834000
  • 收稿日期:2022-08-29 修回日期:2022-09-22 出版日期:2022-12-01 发布日期:2022-11-22
  • 作者简介:雷海艳(1987-),女,四川蓬溪人,高级工程师,硕士,油气勘探,(Tel)13689970696(E-mail)lhy1987@petrochina.com.cn
  • 基金资助:
    国家科技重大专项(2017ZX05001-004);中国石油科技重大专项(2019E-0601)

Genesis and Petroleum Significance of Silica-Rich Shale in Fengcheng Formation of Well Maye-1,Mahu Sag

LEI Haiyan(), QI Jing, ZHOU Ni, CHEN Jun, MENG Ying, ZHANG Xixin, CHEN Ruibing   

  1. 1. Xinjiang Key Laboratory of Shale Oil Exploration and Development, Karamay, Xinjiang 834000, China
    2. Research Institute of Experiment and Detection, Xinjiang Oilfield Company, PetroChina, Karamay, Xinjiang 834000, China
  • Received:2022-08-29 Revised:2022-09-22 Online:2022-12-01 Published:2022-11-22

摘要:

准噶尔盆地玛湖凹陷玛北斜坡区玛页1井风城组发育富硅页岩,以富集自生硅质为特征,富硅页岩层段是该区页岩油分布最广的层段。利用岩心描述、岩石薄片鉴定、电镜扫描、古生物分析、地球化学测试等资料,采用多尺度岩矿学和地球化学结合的方法,对玛北斜坡区风城组富硅页岩纵向分布、自生硅质成因、富硅页岩中藻类的类型和生烃情况以及与硅质相关的孔隙结构展开了研究。结果表明,玛页1井风城组自生硅质的发育与碱湖pH值较高有关,火山物质和陆源碎屑在高pH值条件下易释放溶解硅,在持续蒸发或pH值降低条件下重新结晶形成富硅页岩。富硅页岩中的硅质条带和团块中发育大量保存完好的球形生物化石,为古盐藻休眠孢子,生烃效果显著。富硅页岩脆性较高,发育裂缝、晶间孔和晶间溶孔。玛页1井风城组自生硅质在生烃和成储过程中发挥着重要作用,该研究结果可为玛北斜坡区风城组页岩油的进一步勘探提供借鉴。

关键词: 准噶尔盆地, 玛湖凹陷, 玛页1井, 风城组, 页岩储集层, 富硅页岩, 成因, 油气意义

Abstract:

Silica-rich shale is developed in the Fengcheng formation of Well Maye-1 in the Mabei slope of the Mahu sag, Junggar basin, and it is characterized by enrichment of authigenic silica. The silica-rich shale interval is one of the intervals with shale oil widely distributed. Based on the data from core description, rock thin section, scanning electron microscope, paleontological analysis, and geochemical test, the Fengcheng formation silica-rich shale in the Mabei slope was investigated from the aspects of longitudinal distribution, authigenic silica genesis, algae types and hydrocarbon generation and silica-related pore structure by combining petrology and geochemistry in multiple scales. The results show that the development of the authigenic silica in the Fengcheng formation of Well Maye-1 is related to the high pH of the alkaline lake. Volcanic materials and terrigenous debris are likely to release dissolved silica under high pH conditions, which will form silica-rich shale after recrystallizing because of continuous evaporation or pH reduction. A large number of well-preserved spherical biological fossils developed in the flint strips and agglomerates of the silica-rich shale are mainly composed of dormant spores of paleosalina, which have a remarkable hydrocarbon generation capability. Fractures, intercrystalline pores, and intercrystalline dissolved pores are found in the silica-rich shale which has a high brittleness. The authigenic silica in the Fengcheng formation of Well Maye-1 played an important role in the process of hydrocarbon generation and reservoir formation. This recognition can provide references for the further exploration of shale oil in the Fengcheng formation in the Mabei slope.

Key words: Junggar basin, Mahu sag, Well Maye-1, Fengcheng formation, shale oil reservoir, silica-rich shale, genesis, petroleum significance

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