Abstract:

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.

Key words: exploration potential, petroleum geology, foreland basin, Peru