Abstract:

 Napo Formation in south block of Oriente basin can be divided into 5 sequences according to sequence boundaries，such as unconformity and seismic reflective characteristics. Shelf margins systems tracts, marine  transgressive and highstand systems tracts can be subdivided by the stacking patterns of stratigraphy, changes of lithology and lithofacies. Shelf margin systems tract is characterized by the tidal flat，lacustrine transgressive systems tract is charaterized by the wide spread of marine mudstone sedimentation, and highstand systems tract is featured by the subaqueous shoal sandstone.It is identified that tide channel sandstone is the high quality reservoirs in south block, tide channel sandstone,M1 lithologic pointout zones,subaqueous shoal sandstone are the favorable lithologic traps. The oil shale of the Napo Formation marine shale can offer platitudinous hydrocarbon. The south block locates in the favorable directional zone of oil and gas migration. Hydrocarbon accumulation is in condition of poolforming. Tide channel sandstone growing area is the beneficial exploration directions by integrated forecasting.

Key words:  , Ecuador；Napo Formation；sequence stratigraphy；lithologic and stratigraphic trap