二连盆地侏罗系烃源岩地球化学特征及油源贡献

Geochemical Characteristics and Oil-source Correlation of the Jurassic Source Rocks in the Erlian Basin

二连盆地侏罗系烃源岩研究程度较低,但在侏罗系发现有工业油流。本文通过有机岩石学与有机地球化学常规分析,系统研究与评价了此套烃源岩;结合原油与烃源岩的生物标志化合物的对比与分析,探讨其对油源的贡献。结果表明,二连盆地上侏罗统烃源岩有机质丰度低,有机质类型以Ⅲ型为主,成熟度较低,为非或差烃源岩;中下侏罗统有机质丰度较高,有机质类型以Ⅱ2-Ⅲ型为主,成熟度较高,为较好-好烃源岩。侏罗系烃源岩形成于淡水的氧化沉积环境,以陆源高等植物输入为主。此外,阿56井阿尔善组部分原油和图参1井侏罗系原油来源于侏罗系烃源岩。由此推断二连盆地侏罗系烃源岩具有良好的生烃潜力,勘探前景广阔。

Although the exploration of the Jurassic source rock in the Erlian Basin is limited,industrial oil sources were discovered in this layer recently.This paper studied the oil source correlation in the Jurassic Formation through carrying organic petrology and geochemical analyses and studying the biomarker characteristics of crude oils and source rocks.The results indicated that the lower and the middle Jurassic source rocks have higher content of organic matters,higher maturity and better potential of hydrocarbon producing than those of the Upper Jurassic source rocks,which were deposited in oxidation lacustrine environment and dominated by terrestrial higher plants input.In addition,the crude oils in the Jurassic Formation from the Well A56and the Well Tucan 1are originated from the Jurassic source rocks.In summary,the Jurassic Formation source rocks have well exploration prospect.