Compositions and Geochemical Characteristics of Light Hydrocarbons in Northern Slope of Tazhong

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  • (1. Department of Geochemistry, Yangtze University, Jingzhou 434023, China; 2. Ministry of Education Key Laboratory of Exploration Technology for Oil and Gas Resources, Yangtze University, Jingzhou 434023, China)

Received date: 2008-05-06

  Revised date: 2008-08-01

  Online published: 2008-10-10

Abstract

The crude oils in the northern slope of Tazhong generated from sapropel type organic materials are characterized by low sulfur and less wax. The contents of benzene and dimethylcyclopentane are low; and hexane, cyclohexane and normal heptane have a high content, which reflects that hydrocarbons are mainly from algae and bacteria. The ratio K1 is around 1, and its distribution is basically consistent with the conclusion reported by Mango about light hydrocarbons, but the K1 value of Tazhong 24 well is a bit high, deviating from the conclusion. Meanwhile, the ratio K2 is generally low, and the average value is 0.21, suggesting the oils present typical marine oils’ characteristics. Heptane value is more than 30% and isoheptane value is also greater than 2.0, which indicates that the oils are in the high mature stage. Noteworthy, the high Heptane and isoheptane values represent that the oils did not undergo intensive biological degradation.

Cite this article

WANG Xiang,; ZHANG Min,; LIU Yu-hua,  . Compositions and Geochemical Characteristics of Light Hydrocarbons in Northern Slope of Tazhong[J]. Natural Gas Geoscience, 2008 , 19(05) : 713 -717 . DOI: 10.11764/j.issn.1672-1926.2008.05.713

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