The Kongdian Formation in the Bamianhe area has necessary conditions for oil and gas accumulation

such as reservoirs

traps and sealing conditions

but it lacks hydrocarbon generation conditions.Oil in the Kongdian Formation of the Bamianhe area is characterized by low density

low viscosity

low sulfate content

high wax content and high freezing point and can correlate with that in the Kongdian Formation of the Wangjiagang area in the Dongying depression.According to the contrast of geochemical indicators

such as the nature of crude oil

the constitution of component and the biomarker between the Kongdian Formation and Shahejie Formation of the Bamianhe area

we believe that crude oil sourced from the lower 4

th

 member of Shahejie Formation ( Es

4

) and the 2

nd

 member of the Kongdian Formation (Ek

2

) of the Dongying depression migrated to the Bamianhe area along unconformities and favorable passageways which consisted of the Northwest palaeostructure crest and channel sand body.Therefore

a variety of reservoir types were formed with the majority of overlapping unconformity stratigraphic reservoirs and structural reservoirs.Controlled by structural setting

carrier system

reservoir distribution

trap distribution and fault activities

oil/gas in the Kongdian Formation are mainly distributed in the southwestern part of the nose structure zone horizontally and in the lower part of the Kongdian Formation vertically which are within 80 m of distance from the unconformity.These oil pools are featured by insufficient charging and small scale.