秘鲁三个前陆盆地油气地质条件对比

Maranon、Ucayali和Madre de Dios盆地是3个弧后前陆盆地，对比研究发现：(1)古近纪和新近纪的构造运动对Ucayali盆地的影响比Maranon盆地要大。Maranon盆地西边界的古生代地层被大断层裂开，除了在老构造上有低幅度褶皱外并未明显被反转或压缩；而在Ucayali盆地内，则发育基底相关的逆冲褶皱和反转构造。(2)三叠纪期间，Maranon和Ucayali盆地的大部分地区，大的断裂和构造抬升交替保存和剥蚀着原古生代的地层，而在Madre de Dios盆地，很少有断层产生或抬升剥蚀，导致Madre de Dios盆地古生代地层比Maranon和Ucayali盆地保存较好。(3)自北向南3个盆地的主力烃源岩和主力储层的地层年代越来越老。盆地的前渊带，储层埋藏深度大和成岩作用强的特点导致储层的物性明显变差。(4)晚白垩世以来的挤压和冲断运动在3个盆地的中西部形成了大量中-高幅度的背斜、断背斜等构造圈闭。盆地东部的地层向克拉通地台方向逐层超覆，发育地层圈闭。Maranon和Ucayali盆地北部, 新近纪的构造挤压运动影响到基底，使断层贯穿至盆地基底，发育与基底相关的断层，而在Ucayali盆地的最南部发育薄皮式断层。最后，指出了3个盆地下一步勘探的领域和方向。

Comparison of Petroleum Geology and Exploration Potential of Three Foreland Basins in Peru

Maranon, Ucayali and Madre de Dios basins are Sub Andean foreland basins.The key results of study show that: (1)The tectonic events at the end of Tertiary formed the basement involved thrusts and reverse structures in Ucayali basin, while the effects on Maranon basin are less intensive. (2)During the Triassic period, most Paleozoic formations in Maranon and Ucayali basins are uplifted and eroded, while in Madre de Dios basin, Paleozoic formations are unaffected and relatively well preserved. (3)Generally, the main source rocks and reservoirs for the three basins become older from north to south. And the reservoir quality of foredeep region are relatively poor due to deep burying and diagenesis. (4)Anticlinal and faulted anticlinal traps are formed in the western and middle parts of the foreland basins because of compressive tectonic events, while stratigraphic traps developed in the east of the basin. Basement involved thrusts predominated in the Maranon basin and the northern part of Ucayali basin,which were caused by the Tertiary compression and uplift, while thin skinned thrusting are characterized in the southern part of Ucayali basin. Finally, the exploration targets are pointed out with the comparison results of the three basins. Three exploration targets exist in Maranon basin, including thrustfold foredeep belt, carbonate reservoir in Pucara Formation as well as Cretaceous reservoir without the background of hydrocarbon accumulation in Paleozoic, and reservoir below Chonta Formation. Four types of exploration leads exist in Ucayali basin: traps in thrustfold foredeep belt, Carbonate reservoir in Pucara Formation, as well as gas prospects of Permian formation in North Ucayali sub basin, and Cretaceous stratigraphic traps in the eastern part of the basin. And structures with inherited Paleozoic uplift in the foreland slope are main exploration targets in Madre de Dios basin.