古地理学报 ›› 2020, Vol. 22 ›› Issue (4): 697-714. doi: 10.7605/gdlxb.2020.07.068

• 构造古地理学及古构造 • 上一篇    下一篇

准噶尔盆地西北部P-T转换期不整合的发育演化特征及意义*

李攀1, 李永强2, 经俭波3, 曹正林1, 袁选俊1   

  1. 1 中国石油勘探开发研究院,北京 100083;
    2 中国石油东方地球物理公司研究院乌鲁木齐分院,新疆乌鲁木齐 830016;
    3 中国石油西部钻探地质研究院,新疆克拉玛依 834000
  • 收稿日期:2019-07-01 修回日期:2019-12-25 出版日期:2020-08-01 发布日期:2020-08-10
  • 作者简介:李攀,男,1985年生,博士,2017年毕业于英国阿伯丁大学(University of Aberdeen),现就职于中国石油勘探开发研究院,主要从事层序地层学与沉积学方面的研究工作。E-mail: lipanccc@126.com。
  • 基金资助:
    *国家科技重大专项(编号: 2017ZX05001)资助

Unconformities formed during the P-T transition in the northwestern Junggar Basin: Nature, evolution and implications

Li Pan1, Li Yong-Qiang2, Jing Jian-Bo3, Cao Zheng-Lin1, Yuan Xuan-Jun1   

  1. 1 Research Institute of Petroleum Exploration and Development,PetroChina,Beijing 100083,China;
    2 Urümqi Branch,Geophysical Research Institute,BGP,CNPC, Urümqi 830016,China;
    3 Geological Research Institute of Western Drilling,CNPC,Xinjiang Karamay 834000,China
  • Received:2019-07-01 Revised:2019-12-25 Online:2020-08-01 Published:2020-08-10
  • About author:Li Pan,born in 1985,received a Ph.D. in 2017 from the University of Aberdeen,UK and is now working at the Research Institute of Petroleum Exploration and Development,PetroChina in Beijing. His main research focus is sequence stratigraphy and sedimentology. E-mail: lipanccc@126.com.
  • Supported by:
    National Science and Technology Major Project(No.2017ZX05001)

摘要: 二叠纪晚期—三叠纪早期是准噶尔盆地演化的重要转换期,发育了具有特色性的不整合面。本研究以该盆地的西北部为例,综合利用地震和钻井资料,探讨该时期不整合的发育演化特征及其地质意义。研究表明,转换期发育P3/P2期主要不整合与T1/P3期次要不整合,它们在研究区北部叠加复合,构成了三叠系底界叠合不整合面,在南部被上二叠统所分隔而独立存在;转换期经历了主要不整合的形成、主要不整合被上二叠统超覆、次要不整合与叠合不整合的形成及其被三叠系最终超覆4个演化阶段。不整合的发育演化特征揭示了晚海西期和早印支期构造运动对准噶尔盆地影响的强弱程度、地层记录的“楔形体”内涵以及上二叠统与下三叠统的层序归属。P-T转换期不整合面及其相邻地层形成了有效的油气运移通道、良好的储盖组合和类型众多的圈闭,因此具有重要的油气勘探意义。

关键词: 玛湖凹陷, 百口泉组, 乌尔禾组, 不整合面, P-T转换期

Abstract: Late Permian to Early Triassic represents a significant transition period of the Junggar Basin,resulting in the formation of widespread characteristic unconformities. In this paper,the nature,evolution and implications of these unconformities in the northwestern Junggar Basin are explored,based on seismic and borehole data. This study shows that during the P-T transition two main phases of unconformities were present in the study area,including P3/P2 and T1/P3,with the former expressed mainly as a major angular unconformity and later as a minor parallel or sub-parallel unconformity. Noticeably,the two unconformities are amalgamated to form a superimposed one beneath the Lower Triassic in the north,whereas in the south they co-exist with the Upper Permian in between. Their evolution is characterized by four distinct stages: formation of the major unconformity,its partial onlapping by the Upper Permian,formation of the minor and superimposed unconformity,and their onlapping by the Triassic. The nature and evolution of these unconformities help elucidate the relative influence of the late-stage Hercynian and early-stage Indosinian orogenies,the wedge-shaped connotation of stratigraphic record,and the assignment of tectonic sequences to the Upper Permian and Lower Triassic. The results from this study also indicate that the unconformities and relevant stratigraphy during the P-T transition comprise favorable oil-gas migration pathways,reservoir-seal assemblages and various traps,and are thus of great significance for hydrocarbon exploration.

Key words: Mahu sag, Baikouquan Formation, Wuerhe Formation, unconformity, P-T transition

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