摘要
通过对焦石坝地区JYA井五峰-龙马溪组页岩岩心样品进行现场解吸,计算页岩的总含气量,同时分时段采集解吸气样品进行气组分和稳定碳同位素测定.研究结果表明:1)研究区含气量较高,成分以甲烷为主,为典型干气,含气量主要受控于矿物组成、有机碳含量和含水饱和度等;2)页岩解吸气组分随着解吸时间呈规律性变化,CH4和C2H6含量逐渐升高,CO2含量先降低后升高,N2含量逐渐降低;3)解吸气中δ^13C1和δ^13C2会出现不同程度的分馏现象,主要受控于吸附-解吸过程;4)不同岩相页岩气解吸过程存在差异,在一阶解吸阶段,富泥硅质混合页岩样品的δ^13C1由重变轻,而富硅质页岩样品由轻变重,这可能由于富泥硅质混合页岩无机孔占主导,孔径较大,游离气占总含气量比例较大.
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 δ^13C1 and δ^13C2 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 δ^13C1 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.
作者
青加伟
徐尚
李一啸
舒志国
苟启洋
王雨轩
程璇
QING Jia-wei;XU Shang;LI Yi-Xiao;SHU Zhi-guo;GOU Qi-yang;WANG Yu-xuan;CHENG Xuan(Key Laboratory of Structure and Oil-Gas Resources,China University of Geosciences,Wuhan 430074,China;School of Resources,China University of Geosciences,Wuhan 430074,China;Jianghan Oilfield Company,Sinopec,Qianjiang 433124,Hubei Province,China)
出处
《地质与资源》
CAS
2019年第6期561-569,共9页
Geology and Resources
基金
国家自然科学基金重大项目子课题“富有机质页岩孔隙、裂隙演化与页岩气差异富集机理”(41690134)
国家自然科学基金创新群体项目“油气成藏机理”(41821002)
国家自然科学基金青年基金“四川盆地焦石坝地区页岩气差异富集机理”(41702155)
国家科技重大专项“页岩气区域选区评价方法研究”(2016ZX05034002-003)
关键词
页岩气
解吸气
碳同位素
岩相
焦石坝地区
四川盆地
shale gas
desorbed gas
carbon isotope
lithofacies
Jiaoshiba area
Sichuan Basin
