焉耆盆地博湖坳陷侏罗系烃源岩地化特征及生烃潜力

应用有机地球化学的多种分析方法,对焉耆盆地博湖坳陷中、下侏罗统西山窑组(J2x)、三工河组(Jts)和八道湾组(JIb)煤系烃源岩进行评价.分析表明,其烃源岩有机质丰度都比较高,西山窑组和三工河组评价为中等生油岩,八道湾组评价为好生油岩；有机质类型以Ⅲ型干酪根为主,辅以少量的Ⅱ2型；大多数有机质都处于生油门限内,其中西山窑组处于低熟阶段,三工河组烃源岩部分达到成熟阶段,八道湾组烃源岩基本都处于成熟阶段、为油气生成高峰期.通过对三大生烃次凹及三个层组生烃能力的对比研究,确立了八道湾组是焉耆盆地区域性主力烃源岩的地位；同时指出,七里铺次凹的三工河组烃源岩有机质丰度高、类型稍好、熟演化程度适中,和八道湾组类似也具备较大的生烃能力,是七里铺次凹油气源的有力补充.结合近年勘探成果,指出七里铺次凹两侧的构造高部位及斜坡带是勘探的有利区带.

Geochemical characteristics and hydrocarbon generation potential for the Jurassic source rocks of Bohu depression in Yanqi Basin

This paper evaluated the coal measure source rocks of the Middle and Lower Jurassic Xishanyao Formation,Sangonghe Formation and Badaowan Formationin of Bohu depression in Yanqi Basin by using many organic geochemical methods.The results showed that the source rocks are higher in abundance of organic matter.The Lower Jurassic Badaowan Formation is good source rock,while the Xishanyao and Sangonghe formations are moderate source rock.The types of organic matter are dominated by kerogen Ⅲ with few kerogenⅡ2.Most of the organic matters are within oil window.The organic matters in the Xishanyao Formation are low mature;that in the Sangonghe Formation are partly mature,and that in the Badaowan Formation are mature and in peak oil-generation stage.By comparison of the hydrocarbon generation capacity of the three subsags and the three Formations,the Badaowan Formation is identified as the main source rocks in Yanqi basin.In addition,similar with the source rocks in the Badaowan Formation,the source rocks in the Sangonghe Formation of Qilipu subsag also have high TOC,good organic matter type,suitable thermal maturity,thus have great potential for hydrocarbon generation.According to exploration experiences in recent years,the area along both sides of the structural highs and slope zones of Qilipu subsag is favorable exploration play.