准噶尔盆地古近系生烃潜力与油气源特征研究

Hydrocarbon potential and oil-gas source characteristics of the Palaeogene in the Junggar Basin,Xinjiang

准噶尔盆地古近系是该盆地的一个潜在勘探层系,本文研究了研究区古近系烃源岩的生烃潜力及油气源特征。结果表明,准噶尔盆地古近系发育一定数量和规模的泥质烃源岩,有机质丰度达到了中等-好质量标准,类型以I型和Ⅱ型为主,目前主体处于低成熟-成熟演化阶段,因此具有一定的生烃、生油潜力。这得到了油气源对比研究的印证,典型油气地球化学特征均表现为油型,且为低成熟度,因此只能与古近系烃源岩对应,从而判断为古近系来源。这些油气主要分布在盆地南缘古近系烃源岩埋深较大区,表现出在"源控"基础上受成熟度影响的特征。准噶尔盆地古近系的油气勘探应以原油为主,并且重点目标区在南缘,特别是四棵树凹陷区。这些基础数据和认识还可供全球其它古近系含油气系统研究类比参考。

The Palaeogene strata are interpreted to be potential target strata for hydrocarbon exploration in the Junggar Basin, Xinjiang. The present paper presents a preliminary study of hydrocarbon-generating potential and oil and gas sources in the Palaeogene strata in the Basin. The results of research show that the mudstones as source rocks occur in quantities and scales in the Palaeogene strata, and are characterized by moderate to higher total organic carbon contents, oil-prone I-type and II-type organic matter, and immature to mature levels in the Junggar Basin. The oil and gas appear significantly in the deeper-seated Palaeogene source rocks in the southern Junggar Basin, and are controlled by source rock maturity and deposition. The future oil and gas exploration in the Junggar Basin should be focused in the southern Junggar Basin, especially in the Sikeshu depression. The results of research in this paper may provide a useful reference for the research of the world-wide Palaeogene petroleum systems.