石油与天然气地质 ›› 2018, Vol. 39 ›› Issue (4): 676-684.doi: 10.11743/ogg20180405

• 油气勘探 • 上一篇    下一篇

渤海海域沙西北地区潜山油源及成藏特征

王奇1,2, 郝芳1,2, 徐长贵3, 韦阿娟3, 孙中恒4, 操义军4, 邹华耀4   

  1. 1. 中国石油大学(华东) 地球科学与技术学院, 山东 青岛 266580;
    2. 海洋国家实验室 海洋矿物资源评价与探测技术功能实验室, 山东 青岛 266071;
    3. 中国海洋石油有限公司 天津分公司, 天津 300452;
    4. 中国石油大学(北京) 油气资源与探测国家重点实验室, 北京 102249
  • 收稿日期:2016-06-20 修回日期:2018-01-05 出版日期:2018-08-28 发布日期:2018-07-23
  • 通讯作者: 邹华耀(1963-),男,教授,油气藏形成机理与分布规律;E-mail:huayaozou@cup.edu.cn E-mail:huayaozou@cup.edu.cn
  • 第一作者简介:王奇(1986-),男,博士,油气藏形成机理与分布规律。E-mail:wangqi@upc.edu.cn。
  • 基金项目:
    国家科技重大专项（2016ZX05024-003-008）；中国博士后科学基金项目（2018M630810）。

Origin and accumulation characterization of petroleum in buried hill reservoirs in Shaxibei area,Bohai Sea

Wang Qi1,2, Hao Fang1,2, Xu Changgui3, Wei Ajuan3, Sun Zhongheng4, Cao Yijun4, Zou Huayao4   

  1. 1. School of Geosciences, China University of Petroleum(East China), Qingdao, Shandong 266580, China;
    2. Laboratory for Marine Mineral Resources, Pilot National Laboratory for Marine Science and Technology, Qingdao, Shandong 266071, China;
    3. Tianjin Branch of CNOOC Ltd., Tianjin 300452, China;
    4. State Key laboratory of Petroleum Resources and Prospecting, China University of Petroleum(Beijing), Beijing 102249, China
  • Received:2016-06-20 Revised:2018-01-05 Online:2018-08-28 Published:2018-07-23

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摘要： 综合地质与地球化学方法，探讨了渤海海域沙西北地区潜山的油气来源及成藏特征。生物标志物参数表明沙西北地区已发现的原油位于沙河街组。曹妃甸2-1油田的潜山储层岩性为碳酸盐岩，潜山的原油具有高的伽马蜡烷指数（G/H）以及相对低4-甲基甾烷参数（4MSI），具有相对轻的正构烷烃碳同位素值（整体轻于-29‰），主要为沙河街组一段（沙一段）的油源。曹妃甸1-6油田为花岗岩潜山储层，潜山的原油具有相对高的4MSI（>0.4），正构烷烃的碳同位素值偏重（重于-29%），可能指示着以沙三为主的油源。曹妃甸2-1潜山直接披覆沙一段，沙一段源岩生成的原油可近距离充注至潜山储层中，为披覆式的源储对接成藏模式。曹妃甸1-6油田上覆为东营组，其丰度与热演化程度低，主要作盖层。歧口凹陷的原油侧向通过砂体运移侧向充注至曹妃甸1-6潜山圈闭中，表现为侧向砂体输导油气成藏特征。通过岩心观察和铸体薄片实验分析了CFD2-1-2井潜山风化壳结构特征，揭示了沙西北地区潜山风化壳结构可能不具备侧向长距离输导油气的能力，与潜山直接披覆接触的有效烃源岩或者发育沟通源储的砂体是潜山油气成藏的基础。

关键词: 油源, 成藏模式, 潜山, 沙西北地区, 渤海海域

Abstract: The study discussed the origin and accumulation characteristics of hydrocarbon in buried hills in Shaxibei area,Bohai Sea,through geological and geochemical research methods.Analysis of biomarker parameters reveals that the proved buried hill oil samples in Shaxibei area originate from the Shahejie Formation source rocks.Oil samples from the CFD2-1 buried hill carbonate reservoir have a high G/H index and relatively low 4MSI,and are characterized by depleted 13C for n-alkanes(less than -29‰ as a whole).Such characteristics may be an indicator of the oil origin from the Es1 source rocks.Oil samples, taken from the granite reservoir of the CFD1-6 oil fields,are typified by relatively higher 4MSI (more than 0.4) and heavier carbon isotope of n-alkanes (more than -29‰), which may indicate that CFD1-6 buried hill oil is dominated by the Es3-derived oil. The CFD2-1 buried hill is overlain by the Es1 formation unit,and the mature Es1 source rock may supply adequate petroleum for charging the carbonate reservoirs without long migration distance.This accumulation model can be referred to as the assemblage of generation from the draped source rock and vertically charging to the underlying carbonate reservoir.CFD1-6 granite buried hill is covered by the Ed shale,being characterized by low organic matter abundance and thermal maturity,which can be served as a seal for oil accumulation.Oil generated from the source rock in the Qikou Sag can be transported through the laterally distributed sand body and charge the CFD1-6 buried hill traps,exemplifying a hydrocarbon accumulation model of migration through lateral sand body.On the basis of core observation and casting thin section experiments,we analyzed the textural characteristics of weathered crust from Well CFD2-1-2.The results show that the weathered crust structure in Shaxibei area may not be able to receive the laterally transporting petroleum from sags to buried hill traps,while the overlying effective source rocks on the surface of buried hills or the occurrence of sand bodies communicating source and reservoir are fundamental for hydrocarbon accumulation in buried hills.

Key words: oil kitchen, accumulation model, buried hill, Shaxibei area, Bohai Sea

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