准噶尔盆地车排子地区油气成藏期次研究

Study on Pool-forming Stages of Oil in Chepaizi Area of Junggar Basin

车排子地区位于准噶尔盆地西部,在不同层位发现众多稠油及油气显示,并发现了具有工业价值的轻质油,因此,研究该区的油气成藏期次,对车排子地区的勘探突破具有重要的意义。该区原油按地化特征的差异可分为3类,油源分析表明它们分别来自中下侏罗统混合型烃源岩、中二叠统烃源岩以及中二叠统和中下侏罗统腐泥型烃源岩的混源。在油源分析和烃源岩生烃史模拟的基础上,结合准噶尔盆地及车排子地区构造发育史,将车排子地区油气充注分为4期,即侏罗纪至早白垩世来自中二叠统烃源岩的油气充注成藏、中晚白垩世以来早期形成的稠油发生再次运移形成次生稠油油藏、新近纪早期来自中下侏罗统烃源岩早期生成的少量油气在中生界、古近系和新近系地层充注成藏以及新近纪中晚期至第四纪来自中下侏罗统烃源岩中晚期生成的油气在新近系地层充注成藏。

According to the geochemical characteristics,the oils in Chepaizi Area of Junggar Basin could be classified into three groups,which were generated from the Jurassic mixed-type source rock,the middle-Permian source rock and the middle-Permian & Jurassic sapropel-type source rocks.In terms of oil and source rock correlation,hydrocarbon-generating history of source rocks,as well as the structural history of Junngar Basin,the pool-forming in Chepaizi Area experienced four stage:①the injection of oil from the middle-Permian source rock to the Mesozoic horizon during the Jurassic and early Cretaceous period;②the formation of secondary thick-oil pools after the migration of existed thick oil since the middle-late Cretaceous period;③the injection of a small amount of oil generated earlier from the middle-lower Jurassic source rock to Mesozoic,paleogene and Neogene horizons during the early Neogene period;④the injection of oil generated later from the middle-lower Jurassic source rock to the Neogene horizon during the middle-late Neogene and Quaternary periods.