Geochemistry of deep coal-type gas and gas source rocks in Songliao Basin

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• 作者：Luo Xia ; Sun Fenjin ; Shao Mingli ; Wang Zhihong ; Zeng Fuying ; Zhao Zehui ; Xia Li ; He Feng
• 关键词：Songliao Basin ; deep strata ; coal-type gas ; gas source rock ; geochemical features ; sedimentary environment
• 刊名：Petroleum Exploration and Development
• 出版年：2009
• 出版时间：June 2009
• 年：2009
• 卷：36
• 期：3
• 页码：339-346
• 全文大小：1086 K

文摘

The composition and carbon isotope composition of about 150 natural gas samples reveal that natural gases of deep strata in Songliao Basin are derived from multiple sources and the coal-type gases are widely distributed in the basin. Several gas fields show features of coal-type gases or contain coal-type gases, with δ¹³C₂ being larger than −28 ‰ and δ¹³C_MCC6 being larger than −22‰, such as Shengping gas field in the north of the basin, Xiaohelong and Xiaochengzi gas fields in the south. Organic matter of source rocks in the deep strata is dominantly Type III, with a small portion of Type II. The average TOC of source rocks in the Shahezi (K₁sh) Formation is 1.99 % . Sedimentary facies studies of single wells, which penetrated coals of the Shahezi Formation, indicate that these coals are developed in peat swamps of deltaic plain, depressions between fan deltas, coastal shallow lakes, flooding plain etc, and structures are mainly distributed in the boundary of fault depressions, especially in their slope, some in the center of lakes.