摘要
在对川西拗陷中段天然气轻烃地球化学特征分析基础上,探讨了轻烃在该区天然气研究中的应用。C6轻烃和C7轻烃特征表明天然气为煤型气;利用庚烷值、异庚烷值定性判别成熟度和Mango稳态催化动力学轻烃成因理论方法计算成熟度(Ro为0.83%～1.59%),结果都表明天然气处于成熟和高成熟阶段。天然气苯/正己烷和苯/环己烷值分析表明,从T3x2到J2,天然气存在水溶相和游离相2种运移相态,随深度变浅水溶相运移加强;浅层的J3和K层位天然气以游离相运移为主。轻烃配对参数对比表明:须二段天然气以自生自储为主;须四段天然气主要来自须四段烃源岩,须五段烃源岩有一定贡献,须三段烃源岩贡献较小;侏罗系和白垩系天然气主要来自须五段烃源岩,须四段烃源岩有一定贡献。
Based on the analysis of the geochemical characteristics of light hydrocarbon in natural gas in the middle member of the West Sichuan depression,the authors analyse the applications in studying the light hydrocarbon in the area.The features of C6 and C7 indicate that the natural gas is coal-related gas.The heptane and isoheptane qualitative analysis and the Mango quantity approach（Ro=0.83%~1.59%） show that this natural gas is mature and highly mature gas.The benzene/hexane and the benzene cyclohexane values show that the migration phases are the water-dissolving phase and separate phase.The water-dissolving phase strengthens with depth decreasing from T3x2 Formation to Middle Jurassic.The migration phase is a separate phase in sallow formations of Upper Jurassic and Cretaceous System.The correlation of natural gas and source rocks indicate that the natural gas in T3x2 Formation origins from T3x2 Formation source rocks,and the natural gas in T3x4 Formation mainly origins T3x4 Formation source rocks and some maybe derive from T3x5 Formation source rocks and seldom derive from T3x3 Formation source rock.The natural gas in Jurassic System and Cretaceous System mainly origins T3x5 Formation source rocks and some derives from T3x4 Formation source rocks.
出处
《成都理工大学学报（自然科学版）》
CAS
CSCD
北大核心
2011年第5期500-506,共7页
Journal of Chengdu University of Technology: Science & Technology Edition
基金
国家自然科学基金资助项目(41172119)
关键词
川西拗陷
轻烃
运移相态
天然气成因
气源对比
West Sichuan depression
light hydrocarbon
migration phase
natural gas genesis
gas-source rocks correlation
