地学前缘 ›› 2024, Vol. 31 ›› Issue (2): 343-358.DOI: 10.13745/j.esf.sf.2023.2.54

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塔里木盆地肖尔布拉克组上段烃源岩分布预测及油气勘探意义

徐兆辉1(), 胡素云1, 曾洪流2, 马德波1, 罗平1, 胡再元3, 石书缘1, 陈秀艳1, 陶小晚1   

  1. 1.中国石油勘探开发研究院, 北京 100083
    2.美国得克萨斯大学 奥斯汀分校经济地质局, 美国 奥斯汀 78713
    3.中国石油勘探开发研究院 西北分院, 甘肃 兰州 730020
  • 收稿日期:2022-11-26 修回日期:2023-01-13 出版日期:2024-03-25 发布日期:2024-04-18
  • 作者简介:徐兆辉(1981—),男,博士,高级工程师,主要从事地震沉积学与油气成藏研究。E-mail: zhaohui.xu@petrochina.com.cn
  • 基金资助:
    科学技术部国家科技专项(2016ZX05004);中国石油勘探开发研究院国际合作项目(19HTY5000008);中国石油勘探开发研究院项目(2022KT0102);中国石油勘探开发研究院项目(2016B-04);中国石油勘探开发研究院项目(041021100157);中国石油勘探开发研究院项目(041021120178)

Distribution and hydrocarbon significance of source rock in the Upper Xiaoerbulake Formation, Tarim Basin, NW China

XU Zhaohui1(), HU Suyun1, ZENG Hongliu2, MA Debo1, LUO Ping1, HU Zaiyuan3, SHI Shuyuan1, CHEN Xiuyan1, TAO Xiaowan1   

  1. 1. PetroChina Research Institute of Petroleum Exploration & Development, Beijing 100083, China
    2. Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin, Austin, Texas 78713, USA
    3. PetroChina Research Institute of Petroleum Exploration & Development-Northwest, Lanzhou 730020, China
  • Received:2022-11-26 Revised:2023-01-13 Online:2024-03-25 Published:2024-04-18

摘要:

通常认为塔里木盆地下古生界海相烃源岩以下寒武统玉尔吐斯组泥质岩为主、中下奥陶统泥质岩为辅,下寒武统肖尔布拉克组上段(肖上段)以白云岩储层为主。塔中和塔北地区均钻遇了肖上段泥灰岩,最近钻探的京能柯探1和轮探3井肖上段泥灰岩样品TOC含量多数>0.3%,少量>2%。盆地内不同地区五口井肖上段发育泥灰(云)岩烃源岩,与苏盖特布拉克露头肖上段暗色泥灰岩地化指标(TOC含量是0.41%、Ro是1.14%)一致,表明肖上段泥灰岩具备生烃能力。本文基于露头、地震和钻测井资料,利用地震沉积学理论技术、属性与正演相结合,建立了肖上段台内多期叠置“礁-滩-源”沉积模式。发现烃源岩分布在礁前至坡脚变缓处,连片分布广、叠合厚度大,是规模有效烃源岩,可为邻近储层供烃。经测算,古城三维区肖上段泥灰岩烃源岩总生烃量超亿吨。研究认识拓展了塔里木盆地下古生界海相烃源岩类型、层系和分布范围,提升了寒武系盐下油气资源潜力,坚定了勘探重点从台缘带向台内战略转移的信心,为塔里木盆地古城地区乃至全盆地油气勘探带来新启示。

关键词: 塔里木盆地, 肖尔布拉克组上段, 泥灰岩, 烃源岩, 地震沉积学, 油气勘探意义

Abstract:

It is believed that Lower Paleozoic marine source rock in the Tarim Basin is mainly mudrock of the Lower Cambrian Yuertusi Formation and minor mudrock of the Middle-Lower Ordovician, while the Lower Cambrian Upper Xiaoerbulake Formation is mainly dolostone reservoir rock. Wells drilled in Tazhong and Tabei areas discovered argillaceous limestone in the Upper Xiaoerbulake Formation. Argillaceous limestone samples from recently drilled wells Jingnengketan-1 and Luntan-3 possess high TOC (most exceed 0.3%, some over 2%). Other five wells in different locations in the Tarim Basin reveal effective source rock in argillaceous limestone (and/or dolostone) of the Upper Xiaoerbulake Formation. Evidences from wells agree with dark argillaceous limestone observed in the Upper Xiaoerbulake Formation at the Sugaitebulake outcrop. TOC of the samples selected from the outcrop is 0.41% on average, and Ro 1.14%. The above observations demonstrate the existence of effective argillaceous limestone source rock in the Upper Xiaoerbulake Formation. Based on data from outcrop, seismic, and well, the paper proposes a sedimentary mode of multi-period overlaid reef-shoal-source system in the inner platform in the Upper Xiaoerbulake Formation by means of seismic sedimentology, seismic attributes and forward modeling. According to the findings, source rock is located in the area where dip angle decreases from fore-reef to slope. The argillaceous limestone source rock is wide and thick, which makes it a large-scale effective hydrocarbon source for the nearby reservoir rock. The source rock in Gucheng 3D seismic survey can provide billions of tons of hydrocarbon. The knowledge derived from this paper extends type, stratum and area of Lower Paleozoic marine source rock in the Tarim Basin, elevates hydrocarbon resource potential in the presalt Cambrian plays, strengthens the strategy of transferring exploration focus from platform margin to inner platform, and inspires hydrocarbon exploration in Gucheng area as well as in the Tarim Basin.

Key words: Tarim Basin, Upper Xiaoerbulake Formation, argillaceous limestone, source rock, seismic sedimentology, hydrocarbon exploration significance

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