摘要
准噶尔盆地主要发育石炭系和侏罗系两套煤系烃源岩,形成与之相关的两类煤成气。石炭系煤系烃源岩有机质丰度高,有机质类型主要为Ⅲ型,成熟度高。侏罗系烃源岩分布广,厚度大,成熟度变化大,中下侏罗统是主力气源岩,资源潜力大。石炭系煤成气属干气,碳同位素较重,甲烷碳同位素组成在-30‰左右,乙烷碳同位素组成大于-28‰,为正碳同位素系列,形成自生自储气藏。源自侏罗系煤系烃源岩的天然气分布广,组分相对较湿,甲烷碳同位素组成变化较大,丁烷和丙烷发生倒转的现象较为普遍,反映出天然气的成熟度变化较大,同源不同阶的天然气混合造成重烃碳同位素偏轻。石炭系煤系天然气资源潜力大,是准噶尔盆地今后最主要的天然气勘探领域。源自侏罗系煤系的天然气分布范围广,南缘是今后侏罗系煤系天然气勘探的有利地区。
Carboniferous and Jurassic coal-measure rocks with their relative coal-formed gas are developed in Junggar Basin. Carboniferous source rocks have high organic material abundance, Type Ⅲ organic material, and high maturity. Jurassic source rocks are widely distributed with big thickness and great maturity variety. The Middle and Lower Jurassic are the predominant sources of natural gas, and the potential is large. Carboniferous coal-formed gas is dry gas, its carbon isotope is heavy, the methane carbon isotope composition is about --30‰, the ethane carbon isotope composition is above --28‰, the carbon isotope series is positive （δ^13 C1 〈δ^13 〈2〈δ^13 C3 〈δ^13 C4 ）. Gas reservoir is self-generating and self-preserving. Gas from the Jurassic source rocks has wide distribution and is wet. Methane carbon isotope composition varies greatly, and the carbon isotope reversal of butane and propane is common, reflecting that natural gas has different maturity and the mixing of different-maturity natural gas originated from the same source results in the light isotopic values of heavy hydrocarbons. The potential of the Carboniferous rocks is huge, and is the major exploration area. Gas from the Jurassic source rocks is distributed widely and the southern margin of the basin is a favorable area.
出处
《石油勘探与开发》
SCIE
EI
CAS
CSCD
北大核心
2009年第3期365-374,共10页
Petroleum Exploration and Development
基金
国家重点基础研究发展规划“973”项目(2001CB209113)
国家油气重大专项“中国大型气田形成条件、富集规律及目标评价”(2008ZX05007)
关键词
准噶尔盆地
天然气
煤成气
煤系烃源岩
地球化学特征
Junggar Basin
natural gas
coal-formed gas
coal-measure source rock
geochemical characteristics
