| 作 者：汪生秀1,2,3，焦伟伟1,2,3，方光建1,2,3，王 飞1,2,3，张志平1,2,3，王巧丽1,2,3 |
| 单 位：（1 国土资源部页岩气资源勘查重点实验室（重庆地质矿产研究院）；（2 重庆市页岩气资源与勘查工程技术研究中心（重庆地质矿产研究院；（3 油气资源与探测国家重点实验室重庆页岩气研究中心） |
| 基金项目：本文受国家科技重大专项项目“下古生界页岩有机质成熟度、类型及结构分析方法研究”等资助 |
| 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N2、CO2）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δ13C1＞δ13C2＞δ13C3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。 |
| 关键词： |
| Author's Name: Wang Shengxiu, Jiao Weiwei, Fang Guangjian, Wang Fei, Zhang Zhiping, Wang Qiaoli |
| Institution: Chongqing Institute of Geology and Mineral Resources |
| Abstract: |
| Wufeng Formation-Longmaxi Formation is an important sequence in Sichuan and Chongqing area for shale gas exploration. Based on the analysis of chemical component and stable carbon isotope composition of the shale gas acquired by desoption experiments on Wufeng-Longmaxi Formation shale cores from the Souteastern Chongqing, it is discussed for the genetic type of shale gas and the reason for alkane carbon isotopic reversal. The results showed that the methane content is high with a value from 94.33% to 98.96% in Longmaxi Formation shale gas, and the non-hydrocarbon content is low, mainly including N2 and CO2. The drying coefficient is more than 0.98, indicating typical dry gas. The values of carbon isotopes of methane and ethane are -49‰～-24.47‰ and -39.4‰～-29‰ respectively, and the carbon isotopes of C1 to C3 alkane in Well Y1 with good gas-bearing presents complete reversal, but Well Y2 presents normal. According to the statistical criteria，natural gas in the Southeastern Chongqing area is derived from the sapropelic source rocks, which is a result of high-temperature pyrolysis. It is a mixing product of pyrolysis of kerogens and secondary pyrolysis of crude oil，with obvious features of secondary pyrolysis of oil. The reason for complete reversal of carbon isotopic in Well Y1 is the mixing of two gases. Perhaps, it has some relationships with high production of shale gas. |
| Keywords: Gas composition; Stable carbon isotope; Genetic type; Wufeng Formation; Longmaxi Formation;Southeastern Chongqing |
| 投稿时间： 2016-08-02 |
