Eastern Sub-basin of the North Yellow Sea is still in the early stage of exploration

its petroleum geologic conditions are complex

and the main controlling factors of hydrocarbon accumulation are still not clear.Drilling data

petroleum geochemistry

organic phase classification

diagenesis and fluid inclusion thermometry were integrated to determine the main controlling factors of hydrocarbon accumulation.The distribution of source rocks with low to moderate abundance has controlled the area of oil and gas

and the hydrocarbons occur typically adjacent to the source rocks in vertical.But it is difficult for oil and gas to accumulate in the structural zone far away from the “hydrocarbon kitchen” and the main source rock intervals.The sedimentary process of slowly and shallow burial in early stage-intense uplift in middle stage-rapidly and deep burial in late stage affected the distribution of hydrocarbons.This special sedimentary-burial process also controlled the generation-expulsion history and the reservoir evolution history in the Eastern Sub-basin

and resulted in that the events of generation and expulsion and accumulation of hydrocarbon all occurred during the Neogene.Due to the influences of diagenesis and other factors

the major targets had been turned into the low-porosity and low-permeability reservoirs in the Neogene

making it hard for hydrocarbons to migrate in long distance.Therefore

large-scale hydrocarbon migration and accumulation have not occurred in the Eastern Sub-basin.As a whole

the reservoirs in Eastern Sub-basin features in near-source accumulation

so the targets adjacent to the main “hydrocarbon kitchen” have the lower risk of exploration.Therefore

the structural traps and structural-lithologic composite traps of the secondary structures

which are adjacent to “hydrocarbon kitchen” with good reservoirs

can be the favorable targets in the further exploration.