奥连特盆地油气系统特征与勘探潜力

The Characteristics of Hydrocarbon System and Exploration Potential of Oriente Basin

奥连特(Oriente)盆地是南美厄瓜多尔最主要的含油气盆地。主要烃源岩为盆地西部的白垩系Napo组海相黑色页岩和沥青质碳酸盐岩,主要储层为白垩系Hollin组和Napo组砂岩。上白垩统页岩、煤层及致密的碳酸盐岩是主要的盖层。由于经历了早期的拉张和后期的挤压,盆内广泛发育各种逆冲构造、反转构造和与走滑断层相关的断背斜构造,为油气运移聚集提供了良好的圈闭条件。根据制约油气成藏的各种地质要素、地质作用以及其时空关系,认为奥连特盆地上白垩统为一个含油气系统。通过油气系统分析,认为在盆地的南部、中部及东部是下一步油气勘探的潜在目标。

Oriente Basin was one of the most important petroleum basins in Ecuador of South American.Main source rocks in the basin were marine black shale and asphaltene carbonates of Cretaceous Napo Formation and main reservoirs were sandstones of Cretaceous Hollin and Napo Formations,while upper Cretaceous shale,coal and compact carbonate were the major cap rocks.Various thrust tectonics,inversion structures and faulted anticlines related with strike-slip faults were widely developed in the basin because of early extension and later compression movement,which provided good paths for oil migration and accumulation.Based on geologic characters of petroleum systems and their spatial relationship,it is proposed that there exists upper Cretaceous petroleum system in Oriente Basin.And it is believed that there are favorable exploration target zones in the southern,western and eastern parts of the basin.