渝东南地区五峰组—龙马溪组页岩气地球化学特征及其成因分析

发布时间：2018-05-01 06:15

  本文选题：五峰组 + 龙马溪组　； 参考：《海相油气地质》2017年04期

【摘要】：在对渝东南地区五峰组—龙马溪组页岩现场解吸气样的气体组分和稳定碳同位素分析的基础上,对页岩气的成因类型和烷烃碳同位素倒转原因进行了探讨。渝东南地区五峰组—龙马溪组页岩气的甲烷含量高(94.33%~98.96%),非烃组分(主要包括N_2、CO_2)含量较少,干燥系数大于0.98,为典型的干气。甲烷、乙烷碳同位素值的范围分别为-49‰~-24.4‰、-39.4‰~-29‰,含气性较好的武隆地区Y1井气样烷烃气体呈现δ~(13)C_1δ~(13)C_2δ~(13)C_3的碳同位素"完全倒转"特征,含气性较差的酉阳地区Y2井气样烷烃气体基本具正碳同位素系列特征。天然气成因类型判识标志和图版分析表明,渝东南地区五峰组—龙马溪组页岩气为有机质高温裂解的油型气,是早期生成的干酪根裂解气和后期原油裂解气的混合气,这也是引起武隆地区Y1井气样碳同位素倒转的主要原因,同时这也可能与页岩气高产有关。
[Abstract]:Based on the analysis of gas components and stable carbon isotopes of the shale from Wufeng formation to Longmaxi formation in southeastern Chongqing, the origin types of shale gas and the reasons of hydrocarbon carbon isotope inversion are discussed. The methane content of shale gas from Wufeng formation to Longmaxi formation in southeastern Chongqing is 94.330.33 ~ 98.96%, while the content of non-hydrocarbon components (including N2CO2) is relatively small, and the drying coefficient is greater than 0.98, which is a typical dry gas. The carbon isotopic values of methane and ethane range from -49 鈥，

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