Xinjiang Petroleum Geology ›› 2020, Vol. 41 ›› Issue (1): 31-37.doi: 10.7657/XJPG20200105

• OIL AND GAS EXPLORATION • Previous Articles     Next Articles

Hydrocarbon Generation of Jurassic Source Rocks in the Southern Margin of Junggar Basin

MA Wanyun, Dilidaer ROUZI, LI Ji, LIAO Jiande, WANG Haijing, HE Dan   

  1. Research Institute of Experiment and Detection, Xinjiang Oilfield Company, PetroChina, Karamay, Xinjiang 834000, China
  • Received:2019-11-19 Revised:2019-11-29 Online:2020-02-01 Published:2020-03-31

Abstract:

The source rocks in the Lower and Middle Jurassic strata are generally considered as the major source rocks in the southern margin of Junggar basin. In order to deepen the understandings on the hydrocarbon generation features and distribution of the source rocks, the paper teases out the results of sedimentary and geochemical analysis on 9 outcrop sections and the data from 9 wells in the southern margin of Junggar basin, carries out thermal simulation experiments on hydrocarbon generation for mudstone, carbonaceous mudstone and coal, and studies the hydrocarbon generating evolutions of the 3 types of source rocks by combining with oil-source correlation. The study results show that in the southern margin of Junggar basin, medium-good source rocks are developed in the Lower Jurassic Badaowan formation, medium-quality source rocks are mainly distributed in the Middle Jurassic Xishanyao formation and the Lower Jurassic Sangonghe formation and coal acts as the important source rocks of gas. The oil mainly comes from the Jurassic dark mudstone and the mudstone in the Badaowan formation is the best source rock and widely distributed, which should be considered as the major hydrocarbon generation zone. The key gas generation and expulsion period of the Jurassic source rocks was the phase when the vitrinite reflectance reached 0.9%-1.8%, and the Huo-Ma-Tu anticline belt is located in the Jurassic hydrocarbon generating center in the southern margin of Junggar basin, where the vitrinite reflectance is generally higher than 2.0%. Therefore, the Huo-Ma-Tu-Hu anticline belt is the most favorable area for natural gas exploration.

Key words: Junggar basin, Jurassic, Badaowan formation, source rock, hydrocarbon generation evolution, thermal simulation experiment, natural gas

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