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Geoscience ›› 2012, Vol. 26 ›› Issue (4): 723-731.

• Petroleum geology • Previous Articles     Next Articles

Hydrocarbon Generating Potential of Carboniferous Source Rocks in East Part  of North Margin of Qaidam Basin and Their Geological Significance

 ZHANG  Meng-Feng-1, TUO  Jin-Cai-1, ZHANG  Xiao-Jun-2, QIU  Jun-Li-1, TUN  Chen-Jun-1, GUO  Li-Jun-3, JI  Wen-Chao-4   

  1. 1Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics,Chinese Academy of Sciences,
    Lanzhou, Gansu730000, China; 2PetroChina Northwest Institute of Petroleum Geology, Lanzhou,Gansu730020, China;
    3Research Institute of Exploration and Development, Qinghai Oilfield Company, PertoChina, Dunhuang, Gansu736202, China;
    4Technical Monitoring Center, Changqing Oilfield Company,PertoChina, Xian,Shaanxi710018, China
  • Received:2012-04-12 Revised:2012-05-16 Online:2012-08-18 Published:2012-08-24

Abstract:

According to the basic geochemical data of organic abundance, organic type, organic maturity and biomarker,  the organic geochemical characters of the Carboniferous source rocks in east part of north margin of Qaidam Basin are analyzed. Results are as follows: (1)The darkcolored mudstone has an average organic carbon content of 1.26% and the organic matter is mainly of Ⅲ and Ⅱ types; (2)The carbonate rocks has a low organic carbon content with an average of 0.24%, and the organic matter is of ⅡandⅠtypes; (3)Hydrocarbon source rocks with a moderatehigh organic matter maturity, have larger hydrocarbongenerating potential. The darkcolored mudstone and carbonate rocks both reach the standards of good to moderate hydrocarbon source rock. The sedimentary organic matters are dominantly derived from lower hydrobiont and algae, and deposit in a strong reducing environment of saline water. The comparison study of discovered crude oils of north margin of Qaidam Basin indicates that the crude oils in Lenghu area and Nanbaxian oilfield have little contribution from Carboniferous source rocks. In Mabei oilfield, some crude oil samples are from the Carboniferous source rocks, indicating new petroleum exploration area in north margin of Qaidam Basin.

Key words: east part of north margin of Qaidam Basin, Carboniferous, source rock, petroleum geochemistry, oilsource correlation