Sandbodies in Niuzhuang sag are mainly distributed in deep sag

area between deep sag and gentle slope zone

as well as central low upwarped area. They can be divided into 3 types

i.e. subaqueous alluvial fan

deep water turbidity fan

and frontal slump turbidity fan

of which the subaqueous alluvial fan sandbodies are thick and have good poroperm characteristics and oil/gas shows

while the oil/gas shows in deep water turbidity fan sandbodies are poorer

and that in slump turbidity fan sandbodies are the poorest. The main factors that control oil/gas shows in sandbodies are burial depth

sedimentary facies and types of sandbodies

as well as structural setting

poroperm characteristics and pressure of sandbodies. Reserves and oil saturation in sandbodies would significantly be heightened along with the increasing burial depth. The better the sandbodies'poroperm characteristics are

the better the oil/gas shows would be. They would also be significantly improved with increasing pressures. They are good in the deep sag

and become poorer towards the gentle slope zone

and become the poorest in the central low upwarped zone.