摘要
鄂尔多斯盆地进入源内非常规油气勘探阶段后,在陇东地区长7_(3)亚段试获多口高产工业油流井,新类型页岩油勘探获得战略性突破,明确页岩油岩相组合特征及其分布规律对深化勘探部署具有重要意义。以陇东地区长7_(3)亚段页岩油储集体为研究对象,通过岩心观察、薄片鉴定、X射线衍射分析和TOC分析等方法对页岩油岩相类型和岩相组合开展了定性描述和定量表征,进一步开展了岩相组合空间展布规律的综合研究,最终建立不同沉积成因岩相组合沉积模式。根据宏观沉积特征、微观矿物组分特征和有机质含量特征,长7_(3)亚段可识别出6种岩相类型,垂向上可划分为4种不同沉积成因的岩相组合类型。在古季风、构造运动、物源供给、地形坡度、流体能量和重力流流体转化等因素共同控制下,不同岩相组合的空间上展布特征具有显著差异性。在频繁构造运动背景下,不同类型岩相组合呈现特定的分布规律,研究区湖盆陡坡富砂区自湖盆坡折带近端至远端深湖区依次发育组合类型Ⅰ、组合类型Ⅱ、组合类型Ⅲ,在湖盆陡坡富泥区附近易形成组合类型Ⅲ,在富凝灰质聚集区附近则易形成组合类型Ⅳ,同时受西南古季风的控制,在深湖区也易形成组合类型Ⅳ。
The Ordos Basin has entered an unconventional intra-source exploration phase,with multiple high-yield industrial wells drilled in the Chang 7_(3)sub-member of Longdong area marking a strategic breakthrough in new-type shale oil exploration.It is of great significance to deepen the exploration and deployment to clarify the lithofacies assemblage characteristics and distribution patterns of shale oil.Taking the shale oil reservoir of the Chang 7_(3)sub-member as the research object,qualitative description and quantitative characterization of the facies types and facies assemblages of shale oil have been carried out through methods such as core observation,thin-section identification,X-ray diffraction analysis and TOC analysis.Further comprehensive research on the spatial distribution of the facies assemblages has been carried out,so as to ultimately establish the deposition patterns of facies assemblages of different sedimentary genesis.Based on macroscopic sedimentary characteristics,microscopic mineral composition characteristics,and organic matter content characteristics,six lithofacies types can be identified in Chang 7_(3)sub-member,and four lithofacies assemblages of different sedimentary origins can be divided vertically.Under the joint control of factors such as paleo-monsoon,tectonic movement,provenance supply,topographic slope and gravity flow transformation,the spatial spreading characteristics of different lithofacies assemblages are significantly different.Under the background of frequent tectonic movements,different types of lithofacies assemblage exhibit specific distribution patterns.Three distinct lithofacies assemblages(TypesⅠ-Ⅲ)exhibit a proximal-to-distal zonation from the lake basin slope break to deep lacustrine zones in sand-rich steep slopes,while TypeⅣdominates tuff-rich and deep lacustrine areas under SW paleo-monsoon influence.Facies association TypeⅣis also easy to form in the deep lake area.
作者
朱立文
辛红刚
冯胜斌
田媛媛
李响
罗顺社
周庆安
ZHU Liwen;XIN Honggang;FENG Shenbing;TIAN Yuanyuan;LI Xiang;LUO Shunshe;ZHOU Qing'an(Exploration and Development Research Institute of Changqing Oilfield Branch Company Ltd.,PetroChina,Xi'an 710018,China;Changqing Branch,Geophysical Research Institute,BGP,PetroChina,Xi'an 710021,China;Cooperative Innovation Center of Unconventional Oil and Gas(Yangtze University),Wuhan 430100,China;School of Geosciences,Yangtze University,Wuhan 430100,China)
出处
《天然气地球科学》
北大核心
2025年第7期1275-1290,共16页
Natural Gas Geoscience
基金
中国石油天然气股份有限公司科技重大专项“陆相页岩油规模增储上产与勘探开发技术研究”(编号:2023ZZ15)资助。
关键词
岩相特征
岩相组合
沉积模式
延长组
鄂尔多斯盆地
陇东地区
Lithofacies
Lithofacies assemblages
Depositional model
Yanchang Formation
Ordos Basin
Longdong area
