The Nangong sag is a NNE-trending dust-pan shaped sag in southern Jizhong Depression.The remnant Paleogene measures 750 km

2

.The sag is a superimposed one composed of Eocene and Oligocene basins

the source rocks of which are Eocene and Oligocene sediments.It has similar petroleum geological condition as Shulu sag near by in which certain amount of hydrocarbon reserves have been found.This suggests that medium or small size of oil and gas fields could be found within the sag

and that Dagaocunarea in the sag should be focused as the main target.Structural-trapped pools may be found in the eastside of the area (fault-structural zone) and lithological-trapped pools may be found in the west side.