地学前缘 ›› 2025, Vol. 32 ›› Issue (5): 131-149.DOI: 10.13745/j.esf.sf.2025.2.3

• 沉积时空再造 • 上一篇    下一篇

塔里木顺南地区上奥陶统斜坡扇体系沉积单元构成及其演化特征

吴鹏飞1,2(), 吴俊1,2,*(), 樊太亮1,2, 刘倩1,2, 张卫国1,2, 杨素举3, 夏永涛3, 兰明杰3   

  1. 1.中国地质大学(北京) 能源学院, 北京 100083
    2.中国地质大学(北京) 海相储层演化与油气富集机理教育部重点实验室, 北京 100083
    3.中国石油化工股份有限公司西北油田分公司勘探开发研究院, 新疆 乌鲁木齐 830011
  • 收稿日期:2024-12-20 修回日期:2025-02-18 出版日期:2025-09-25 发布日期:2025-10-14
  • 通信作者: 吴俊
  • 作者简介:吴鹏飞(2000—),男,硕士研究生,主要从事深水地震沉积学方面的研究。E-mail: 18876059017@163.com
  • 基金资助:
    国家自然科学基金青年科学基金项目(42102151);中央高校基本科研业务费“新教师基本科研能力提升项目(2652022034)”;中国石油化工股份有限西北油田分公司科研项目(KY2022-045-2)

Sedimentary units composition and evolution characteristics of the slope fan system of the Upper Ordovician in the Shunnan area, Tarim Basin

WU Pengfei1,2(), WU Jun1,2,*(), FAN Tailiang1,2, LIU Qian1,2, ZHANG Weiguo1,2, YANG Suju3, XIA Yongtao3, LAN Mingjie3   

  1. 1. School of Energy Resources, China University of Geosciences (Beijing), Beijing 100083, China
    2. Key Laboratory of Marine Reservoir Evolution and Hydrocarbon Enrichment Mechanism, Ministry of Education, China University of Geosciences (Beijing), Beijing 100083, China
    3. Exploration and Production Research Institute, Sinopec Northwest Oil Field Company, Ürümqi 830011, China
  • Received:2024-12-20 Revised:2025-02-18 Online:2025-09-25 Published:2025-10-14
  • Contact: WU Jun

摘要:

塔里木盆地顺南地区上奥陶统发育斜坡扇体系,多口井测试表明该层段存在气测异常,具有油气勘探价值。然而,针对该斜坡扇体系的特征认识不清,在一定程度上延缓了该区油气勘探进程。基于此,本研究综合利用顺南地区高精度三维地震和钻/测井等资料,明确研究区斜坡扇体系的地震与测井响应特征,阐明斜坡扇体系的沉积单元构成,揭示斜坡扇体系的沉积充填演化过程及其控制因素。研究表明:(1)顺南地区上奥陶统斜坡扇体系由水道、砂质朵叶体和泥质朵叶体共3种沉积单元构成,不同沉积单元的地震-测井响应存在显著差异。其中,水道对应中-强振幅、中-低频率和连续性好的“U”型、“V”型下切充填反射,以粉砂岩为主,自然伽马(GR)和声波时差(AC)曲线呈箱型;砂质朵叶体对应中-强振幅、中-低频率和连续性好的层状或丘状反射,以粉砂岩和粉砂质泥岩为主,GR曲线呈中-高值,深侧向电阻率(RD)曲线呈中-低值,两种曲线波动较大;泥质朵叶体对应中-弱振幅、高频率和连续性差的丘型反射或杂乱反射,以泥岩和粉砂质泥岩为主,GR曲线呈高值,RD曲线呈低值,整体波动小。(2)研究区斜坡扇体系共识别了8个砂质朵叶体、两个泥质朵叶体和多条水道。根据不同沉积单元的相互切割关系,将斜坡扇体系的沉积充填过程划分为3期。其中,早期发育1~3号砂质朵叶体和水道,中期发育Ⅰ和Ⅱ号泥质朵叶体、4号砂质朵叶体和水道,晚期发育5~8号砂质朵叶体和水道。(3)构造活动、海平面升降和物源供给控制着顺南地区斜坡扇体系的沉积充填演化进程。其中,构造活动为研究区斜坡扇体系提供了地形条件和物质输送基础,海平面升降控制物源供给量和沉积单元发育位置,物源的物质组成和供给量决定沉积单元类型和发育的规模。(4)顺南地区具有良好的生储盖配置关系,外加走滑断裂有效地改造储集空间并沟通源储间油气运移,指明了油气富集的有利区带位于走滑断裂带附近。

关键词: 沉积单元构成, 沉积演化控因, 斜坡扇体系, 上奥陶统, 塔里木盆地顺南地区

Abstract:

Slope fan system developed in the Upper Ordovician in the Shunnan area of the Tarim Basin. Multiple wells have detected gas anomalies in these strata, indicating its potential value for oil and gas exploration. However, the characteristics of the slope fan system are poorly understood, hindering exploration progress. This study utilized high-precision 3D seismic and logging data from the Shunnan area to clarify the composition of the sedimentary units within the slope fan system and to reveal its evolutionary filling process and controlling factors. The results are as follows: (1) The slope fan system in the Upper Ordovician in the Shunnan area comprises three sedimentary units: channels, sandy lobes, and muddy lobes. These units exhibit significant differences in their seismic and log responses. The channels correspond to “U” and “V” shaped down-cut filling seismic reflections with medium-strong amplitude, medium-low frequency, and good continuity. They are dominated by siltstone, and the GR and AC curves are box-shaped. The sandy lobes correspond to laminar or mound-shaped seismic reflections with similar seismic attributes. They are dominated by siltstone and silty mudstone, with the GR curve showing medium-high values and the RD curve showing medium-low values, both fluctuating significantly. Muddy lobes also correspond to laminar or mound-shaped reflections. They are dominated by mudstone and silty mudstone, with the GR curve showing high values, the RD curve showing low values, and both fluctuating slightly. (2) We identified a total of 8 sandy lobes, 2 muddy lobes, and numerous channels in the slope fan system in the study area. Based on cross-cutting relationships, the sedimentary filling process is divided into three stages: No. 1-3 Sandy lobes and channels were developed in the early stage; No. I and II Muddy lobes, No. 4 sandy lobe, and channels were developed in the middle stage; and No. 5-8 Sandy lobes and channels were developed in the late stage. (3) The evolutionary filling process of the slope fan system was controlled by tectonic activity, sea-level change, and sediment supply. Tectonic activity provided the topographic relief and source of sediments for the system. Sea-level change controlled sediment supply and the location of sedimentary units. Source rock composition and sediment supply determined the types and scales of the sedimentary units. (4) The Upper Ordovician in the Shunnan area has a good source-reservoir-seal assemblage. Furthermore, the strike-slip faults enhance reservoir space and facilitate hydrocarbon migration between source and reservoir rocks, indicating that favorable zones for hydrocarbon accumulation are located near the strike-slip fault zones.

Key words: sedimentary units, controlling factors of sedimentary evolution, slope fan system, the Upper Ordovician, Shunnan area in the Tarim Basin

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