石油学报 ›› 2019, Vol. 40 ›› Issue (4): 434-447.DOI: 10.7623/syxb201904005

• 地质勘探 • 上一篇    下一篇

鄂尔多斯盆地西南部延长组长8油层组层序地层特征及沉积充填模式

陈林1,2, 陆永潮2, 林卫兵3, 邢凤存4, 陈平3, 刘璐5, 胡海燕6, 魏巍2   

  1. 1. 中国地质调查局武汉地质调查中心 湖北武汉 430205;
    2. 中国地质大学(武汉)资源学院 湖北武汉 430074;
    3. 中国地质大学(武汉)海洋学院 湖北武汉 430074;
    4. 成都理工大学沉积地质研究院 四川成都 610059;
    5. 中国石油化工股份有限公司华北分公司勘探开发研究院 河南郑州 450006;
    6. 长江大学地球科学学院 湖北武汉 430100
  • 收稿日期:2018-05-15 修回日期:2019-03-15 出版日期:2019-04-25 发布日期:2019-05-07
  • 通讯作者: 林卫兵,男,1963年2月生,1986年获武汉地质学院地质学专业学士学位,现为中国地质大学(武汉)海洋学院副教授,主要从事储层沉积学层序地层学教学及相关科研工作。Email:475519803@qq.com
  • 作者简介:陈林,男,1989年9月生,2010年获中国矿业大学地质工程专业学士学位,2015年获中国地质大学(武汉)能源地质工程专业博士学位,现为中国地质调查局武汉地质调查中心工程师,主要从事非常规油气储层沉积相及层序地层学研究。Email:chenlin676@163.com
  • 基金资助:

    国家自然科学基金项目(No.41002045)、国家科技重大专项(2016ZX05034-001-002)和中国地质调查局地质调查项目(DD20160194)资助。

Sequence stratigraphy and sedimentary filling model of Chang-8 oil layer of Yanchang Formation in southwestern Ordos Basin

Chen Lin1,2, Lu Yongchao2, Lin Weibing3, Xing Fengcun4, Chen Ping3, Liu Lu5, Hu Haiyan6, Wei Wei2   

  1. 1. Wuhan Center, China Geological Survey, Hubei Wuhan 430205, China;
    2. Faculty of Earth Resources, China University of Geosciences, Hubei Wuhan 430074, China;
    3. College of Marine Science and Technology, China University of Geosciences, Hubei Wuhan 430074, China;
    4. Institute of Sedimentary Geology, Chengdu University of Technology, Sichuan Chengdu 610059, China;
    5. Petroleum Exploration and Development Research Institute, Sinopec North China E & P Company, Henan Zhengzhou 450006, China;
    6. School of Geosciences, Yangtze University, Hubei Wuhan 430100, China
  • Received:2018-05-15 Revised:2019-03-15 Online:2019-04-25 Published:2019-05-07

摘要:

综合鄂尔多斯盆地西南部延长组长8油层组的野外露头、岩心、测井、地震以及分析测试资料,研究了长8油层组的层序地层格架、沉积特征、沉积充填的空间展布及层序控制下的沉积演化模式。结果表明,长8油层组主要发育在长7油层组—长8油层组层序的低位体系域,进一步可划分为6个准层序组,15个准层序。层序地层对比表明,长8油层组在空间上分布稳定,无明显厚度变化,地形起伏较小,发育湖盆边缘缓坡层序构成样式。沉积砂体的成分成熟度和结构成熟度较低,粒度结构具有二段性,为快速堆积产物并发育波浪改造的沉积构造,具有牵引流色彩的密度流沉积特征,沉积中可见浅水虫孔、植物根迹等,总体指示浅水三角洲环境。沉积物具有受季节性气候变化控制的多期洪泛密度流沉积特征。沉积充填的垂向、剖面和平面展布特征显示,在坡缓、浅水和快速堆积的环境下,三角洲前缘区水道在前缘区频繁分叉改道,从而形成网结化前缘分布样式。其中,在长8油层组沉积早期为三角洲主建设进积时期,水道限定性强,河道砂坝广泛垂向叠置;在长8油层组沉积晚期,在湖平面上升的背景下,物源供给能力减弱,研究区内三角洲河流建设作用弱化,水下分流河道、河口坝受较强地改造,沉积物粒度变细,砂体的横向片状展布性增强,以加积作用、进积作用为主。整体上,长8油层组记录了一套完整的水退到水进的陆相湖盆低位充填序列。

关键词: 鄂尔多斯盆地, 延长组, 长8油层组, 层序地层, 沉积充填模式

Abstract:

Comprehensively based on the analysis of outcrop, core, logging, seismic and test data of Chang-8 oil layer of Yanchang Formation in southwestern Ordos Basin, the sequence stratigraphic framework, sedimentary characteristics, spatial distribution of sedimentary filling and the sedimentary evolution model controlled by the sequence of Chang-8 oil layer are investigated. The results show that in Chang-8 oil layer, the lowstand system tract sediments of the Chang-7-Chang-8 sequence is mainly developed, which can be further divided into 6 parasequence sets and 15 parasequences. Sequence stratigraphic correlation shows that the spatial distribution of the stratum is stable, no obvious thickness change and less topographic relief. A sequence structure pattern of gentle slope is thus developed on the margin of lacustrine basin. The sedimentary sand body is characterized by low composition maturity and structure maturity, two segments of grain structure, well-developed sedimentary structures formed by rapid deposition and wave transformations, and density flow deposition with traction flow feature. In addition, it can be visibly seen that shallow water wormholes and plant roots are developed, indicating a shallow water delta environment. Sediments have multi-phase flood density flow sedimentation characteristics controlled by seasonal climate change. The vertical, sectional and planar distribution characteristics of sedimentary fillings reveal that the channels of delta front diverge frequently in the front zone, thus forming the networking distribution pattern under the background of gentle slope, shallow water and rapid deposition. Progradation of delta mainly occurred during the early period of Chang-8 oil layer deposition. The supply of provenance was reducing, so the construction ability of delta was weakened under the background of lake level rising. The channels were highly restrictive, thus the extensive vertical superposition was widely developed at sand body bar. During the late period of Chang-8 oil layer deposition, the subaqueous distributary channels and mouth bars were subject to relatively strong reforming. The grain size of the sediments became finer and the lateral distribution of sand bodies was strengthened. The lateral sheet-spreading distribution of sand bodies is enhanced, dominated by aggradation and progradation. On the whole, the Chang-8 oil layer recorded a complete cycle of lowstand filling sequence of continental lacustrine basin from regression to transgression.

Key words: Ordos Basin, Yanchang Formation, Chang-8 oil layer, sequence stratigraphy, sedimentary filling model

中图分类号: