【摘要】 准噶尔盆地是中国西部典型的多旋回叠合盆地,发育有石炭系、二叠系、三叠系、侏罗系、白垩系和古近系6套烃源岩,同时存在6大类原油和3大类天然气,广泛分布于盆地不同地区。西北缘原油总体相似,碳同位素组成轻(δ¹³C<-29‰),胡萝卜烷、类异戊二烯烷烃、三环萜烷、伽马蜡烷丰富,甾烷以C₂₈、C₂₉为主,基本没有重排甾烷,为第二类原油,来源于二叠系湖相烃源岩。腹部绝大多数原油与西北缘原油相似,但胡萝卜烷、类异戊二烯烷烃、伽马蜡烷等有差异,来源于不同凹陷的二叠系湖相烃源岩;少量原油碳同位素组成重(δ¹³C-28‰^-26‰),Pr/Ph大于2.5,三环萜烷以C₁₉、C₂₀为主,藿烷丰富而伽马蜡烷极低,以C₂₉规则甾烷及重排甾烷为主,为第四类原油,来源于侏罗系煤系烃源岩。东部存在5种类型原油,第一类原油碳同位素组成特别重(δ¹³C>-26‰),来源于石炭系烃源岩;第二类原油与腹部地区绝大多数原油十分相似,来源于二叠系湖相烃源岩;第三类原油碳同位索组成轻,重排甾烷、Ts、C₂₉Ts及C₃₀重排藿烷异常丰富,来源于中上三叠统湖相烃源岩;第四类原油源于侏罗系煤系烃源岩;混合类原油为二叠系、三叠系、侏罗系原油的混合,各自贡献平均分别为20%、15%和65%。南缘存在4类典型原油,为第二、第四、第五和第六类原油,其中第二、第四类分别源于二叠系和侏罗系;第五类原油碳同位素组成轻(δ¹³C<-29‰)、Pr/Ph<1.0、伽马蜡烷丰富且有两个异构体、Ts、C₂₉Ts、C₃₀重排藿烷、C₂₇^C₂₉异胆甾烷及C₃₀甲基甾烷丰富,来源于白垩系湖相烃源岩;第六类原油主要为中低成熟原油,碳同位素组成δ¹³C²8‰^-26‰,C₂₇、C₂₈、C₂₉甾烷呈"V"型分布,甲藻甾烷异常丰富,来源于古近系湖相烃源岩。准噶尔盆地天然气有油型气、混合气和煤型气,前两类主要来源于二叠系湖相烃源岩和石炭系海相烃源岩,煤型气主要来源于石炭系和侏罗系煤系烃源岩。不同类型油气分布与不同时代烃源灶具有良好对应关系:石炭系油气主要分布于陆东-五彩湾;二叠系油气主要分布于西北缘、腹部与东部;三叠系原油仅分布于东部;侏罗系原油主要分布于东部与南部;白垩系原油仅分布于南缘中部;古近系原油仅分布于南缘西部。按照盆地构造特征及不同时代烃源灶与油气关系,将准噶尔盆地划分为西部、中部、东部、南部及乌伦古5个油气系统及15个子油气系统。更多还原

【Abstract】 The Junggar Basin is a typical polycyclic superimposed basin in northwest China,which consists of six sets of source rocks（Carboniferous,Permian,Triassic,Jurassic,Cretaceous and Paleogene） and contains six groups of crude oil and three types of natural gas.The crude oils in the northwestern margin are similar and belong to the Group Ⅱ oil.They have light carbon isotopic composition(δ¹³C<-29‰) and abundant carotenoids,isoprenoids,tricyclic terpanes and gammacerane.Steranes are dominantly C₂₈ and C₂₉ without diasteranes.These crude oils derived from the Permian lacustrine source rocks.Most crude oils in the central part of the basin are similar to those in the northwestern margin,but different in content of carotenoids,isoprenoids and gammacerane,which might be divided into four subgroups.These oils derived from the Permian source rocks in different depressions.A minor amount of crude oil has a heavy carbon isotopic composition(δ¹³C:- 28‰^-26‰) and Pr/Ph>2.5.The tricyclic terpane is composed mainly of C₁₉ and C₂₀.The hopanes are abundant while the gammacerane is extremely low.The steranes are mainly composed of C₂₉ regular steranes and diasteranes.The oil was sourced from the Jurassic coal measures.There are five groups of crude oils in the eastern Junggar.Group I crude oils have a very heavy carbon isotopic composition(δ¹³C>-26‰) and derived from the Carboniferous source rocks.Group Ⅱcrude oils are very similar to most of those in the central region and derived from the Permian lacustrine source rocks.Group Ⅲ crude oils have a light carbon isotopic composition and are abundant in diasterane,Ts,C₂₉Ts and C₃₀ diahopane.They derived from the Triassic lacustrine source rocks.Group Ⅳ crude oils derived from the Jurassic coal measures.The mixed crude oil is a mixture of the Jurassic,Triassic and Permian oils,meanly accounting for 65%,15%and 20%,respectively.There are four groups of typical crude oils in the southern margin,which belong to the Group Ⅱ > Ⅳ,Ⅴ and Ⅵ of crude oil,respectively,with group Ⅱ and group Ⅳ crude oils deriving from the Permian lacustrine source rocks and the Jurassic coal measures,respectively.Group Ⅴ crude oils have a light carbon isotopic composition(δ¹³C<- 29 ‰),Pr/Ph<1.0 and two isomers,with abundant gammacerane.The Ts,C₂₉Ts,C₃₀ diahopane,C₂₇ C₂₉cholestanes and C₃₀ methlysteranes are also abundant.They derived from the Cretaceous lacustrine source rocks.Group VI crude oils with low to medium mature oils have a heavy carbon isotopic composition(δ¹³C:-28‰^-26‰).The C₂₇,C₂₈ and C₂₉steranes are distributed in a V shape.The extremely abundant dinosteranes derived from the Eocene lacustrine source rocks.Natural gases in the Junggar basin can be divided into three types:oil-derived,mixed and coal-derived.The first two types mainly came from the Permian lacustrine source rocks and the Carboniferous marine source rocks.The coal-derived gas came mainly from the Carboniferous and Jurassic coal measures.The distribution of different types of oil and gas in Junggar corresponds to the source kitchen developed in different geological ages.The Carboniferous oil and gas are distributed mainly in the Ludong-Wucaiwan area;the Permian oil and gas are widely distributed,mainly in the northwestern margin,the central region and the eastern area;the Triassic crude oil is limited to the eastern area;the Jurassic crude oil is mainly distributed in the eastern and southern areas;the Cretaceous crude oil is distributed mainly in the central part of the southern margin;the Paleogene crude oil is distributed mainly in the western part of the southern margin.The Junggar basin can be divided into five petroleum systems,i.e.the western,central,eastern,southern and Ulungur petroleum systems,and 15 petroleum subsystems based on the structural features of the basin and the relations between source kitchens of different geological ages and different types of oil and gas.更多还原