塔里木盆地寒武系—奥陶系海相烃源岩识别与分布预测

Identification and distribution of marine hydrocarbon source rocks in the Ordovician and Cambrian of the Tarim Basin

基于露头实测、探地雷达浅层地震测量、岩心分析、测井评价和地震追踪等,建立了海相烃源岩识别方法和流程,对塔里木盆地寒武系—奥陶系海相烃源岩进行重新识别和空间展布预测。结果表明,寒武系—奥陶系垂向上共发育4套烃源岩,分别赋存于阿瓦提凹陷和满加尔凹陷的下—中寒武统、塔东地区的下-中奥陶统黑土凹组、阿瓦提凹陷—阿满过渡带—满加尔凹陷的中-上奥陶统萨尔干组—吐木休克组—却尔却克组、阿瓦提凹陷至塔中地区的上奥陶统印干组—良里塔格组中。寒武系—奥陶系海相烃源岩的发育受海平面上升控制明显,分布具有鲜明的"等时异相"特征,即在同一时期,不同沉积相带沉积不同类型的烃源岩;烃源岩的形成还具有随碳酸盐岩盆地迁移而迁移,随陆源碎屑大量注入而消亡的规律。

A process for identifying marine hydrocarbon source rocks is established based on outcrop measurement,ground-penetrating radar survey,core analysis,logging evaluation,seismic interpretation,etc.It is used to identify the Cambrian and Ordovician marine hydrocarbon source rocks and to predict their spatial distribution in the Tarim Basin.There developed four suites of marine hydrocarbon source rocks in the Tarim Basin,which are distributed,respectively,in the Lower-Middle Cambrian of the Awati and Manjiaer sags,the Heituao Formation of the Lower-Middle Ordovician in the Tadong region,the Saergan–Tumuxiuke–Queerqueke formations of the Middle–Upper Ordovician from the Awati Sag to the Manjiaer Sag,and the Yin’gan and Lianglitage formations of the Upper Ordovician from the Awati Sag to the Tazhong area.The development of these source rocks is controlled by the sea level rise and they are characterized by different facies in the same stage,namely,different source rocks are deposited in sedimentary facies zones at the same stage.The formation of the source rocks migrates with the carbonate basin and stops when there are large quantities of clastics poured in.