Oil & Gas Geology ›› 2008, Vol. 29 ›› Issue (3): 348-354,347.doi: 10.11743/ogg20080310

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Characteristics of the Mesozoic marine source rocks in the Qiangtang Basin,Tibet

Wu Xinhe1, Zhang Li2, Wang Chengshan3, Yi Haisheng4   

  1. 1. Research Institute of Petroleum Exploration & Production, SINOPEC, Beijing 100083, China;
    2. Research Institute of Exploration & Development, Xinjiang Oilfield Company, Petro China, Karamay, Xinjiang 834000, China;
    3. China University of Geosciences, Beijing 100083, China;
    4. State Key Laboratory of Oil/Gas Reservoir and Exploitation Geology, Chengdu University of Technology, Chengdu, Sichuan 610059, China
  • Received:2008-01-29 Online:2008-06-24 Published:2012-01-16

Abstract:

Qiangtang Basin has well-developed thick marine deposits with the Jurassic as the thickest(ten thousand meters).Four sets of high quality source rocks,namely the Triassic Xiaochaka Formation,the Jurassic Buqu,Xiali,and Suowa formations,are extensively distributed in the Mesozoic Qiangtang basin.These source rocks are mainly composed of limestone and mudstone with a maximum thickness over 3000 m.The source rocks in the Upper Triassic Xiaochaka Formation and the Middle Jurassic Buqu Formation have larger thickness and their organic matters are mainly of type Ⅱ with maturity varying from mature to over-mature,and average TOC is over 1.5%.They have favorable burial conditions and are the main hydrocarbon source in the basin.The Jurassic Suowa Formation is also rather thick and its organic matters are of mostly type Ⅰ and Ⅱ,however,the formation was over exposed and not favorable for hydrocarbon generation.There were two peaks of hydrocarbon generation:late Jurassic-early Cretaceous and Neogene.

Key words: source rock, type of organic matter, oil and gas distribution, marine, Mesozoic, Qiangtang Basin

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