GEOCHEMICAL CHARACTERISTICS AND INFLUENCE FACTORS OF DESORBED GAS OF SHALE: A Case Study of JYA Well in Jiaoshiba area, Sichuan Basin
QING Jia-wei1,2, XU Shang1,2, LI Yi-Xiao1,2, SHU Zhi-guo3, GOU Qi-yang1,2, WANG Yu-xuan1,2, CHENG Xuan1,2
1. Key Laboratory of Structure and Oil-Gas Resources, China University of Geosciences, Wuhan 430074, China; 2. School of Resources, China University of Geosciences, Wuhan 430074, China; 3. Jianghan Oilfield Company, Sinopec, Qianjiang 433124, Hubei Province, China
Abstract：Through the desorption of shale core samples from Wufeng-Longmaxi Formation in JYA well of Jiaoshiba area, the total gas content in shale is calculated, and the desorbed gas samples are collected at different times for the determination of compositions and stable carbon isotopes. The results are shown as follows:1) The gas content in the study area is high, which is mainly controlled by mineral compositions, organic carbon content and water saturation, dominated by methane, a kind of typical dry gas. 2) The desorbed shale gas compositions change regularly with desorption time. The contents of CH4 and C2H6 increase gradually, CO2 content first decreases then increases, and N2 decreases gradually. 3) The δ13C1 and δ13C2 in the desorbed gas show different degrees of fractionation, mainly controlled by the "adsorption-desorption" process. 4) The desorption processes of shale gas with various lithofacies are different. At the first stage, the δ13C1 of mud-rich siliceous mixed shale samples changes from heavy to light, while that of the silicon-rich shale samples from light to heavy, which may be due to the inorganic pores that are dominated in the mud-rich siliceous mixed shale with large pore diameter and large proportion of free gas in the total gas content.
青加伟, 徐尚, 李一啸, 舒志国, 苟启洋, 王雨轩, 程璇. 页岩解吸气地球化学特征及其影响因素分析——以四川盆地焦石坝地区JYA井为例[J]. 地质与资源, 2019, 28(6): 561-569.
QING Jia-wei, XU Shang, LI Yi-Xiao, SHU Zhi-guo, GOU Qi-yang, WANG Yu-xuan, CHENG Xuan. GEOCHEMICAL CHARACTERISTICS AND INFLUENCE FACTORS OF DESORBED GAS OF SHALE: A Case Study of JYA Well in Jiaoshiba area, Sichuan Basin. GEOLOGY AND RESOURCES, 2019, 28(6): 561-569.
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2019, Vol. 28 
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