Oil & Gas Geology ›› 2011, Vol. 32 ›› Issue (6): 890-896,908.doi: 10.11743/ogg20110611

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Characteristics of tight carbonate cap rock and its control on hydrocarbon accumulation in the north slope of Tazhong uplift

Zhao Yue1,2,3, Yang Haijun3, Liu Dandan1,2, Han Jianfa4, Zhang Yanping1,2, Zhang Yangchun4, Wang Haijiang4   

  1. 1. College of Geosciences, China University of Petroleum, Beijing 102249, China;
    2. State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Beijing 102249, China;
    3. Petroleum Exploration and Development Research Institute, PetroChina Tarim Oilfield Company, Korla, Xinjiang 841000, China;
    4. Exploration and Development Department, PetroChina Tarim Oilfield Company, Korla, Xinjiang 841000, China
  • Received:2011-01-20 Online:2011-12-28 Published:2012-02-08

Abstract:

Large marine carbonate condensate gas reservoirs occur in the Yingshan Formation in the north slope of Tazhong uplift and their cap rock is tight carbonates in the 3rd-5th member of Lianglitage Formation.The carbonates are distributed widely in the whole north slope of Tazhong uplift,which is massive and is superimposed vertically and connected laterally,sealing the hydrocarbons in the underlying Yingshan Formaiton.Based on analyses of lithology,thickness and clay content of the tight carbonates,we summarized their distribution patterns and relationships with hydrocarbon accumulation and discussed the control of their thickness and clay content on oil/gas distribution.The study shows that the tight carbonate cap rock in the north slope of Tazhong uplift may be efficient seals when its thickness is equal to or more than 80 m and its clay content GR value is over 20 API,Thickness and clay content can complement each other for sealing capacity.

Key words: sealing capacity, cap rock, tight carbonate rock, Lianglitage Formation, Yingshan Formation, the north slop of Tazhong uplift

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