Among the proved reserves in Bohai Sea waters

those from structural hydrocarbon pools account for the most

taking up 66.8% of the total

while complex pools contain second largest reserves (25.9%).The number of the large/medium-sized fields only accounts for 34% of the total

while their proven reserves account for 84.4% of the total.Proven reserves are most numerous in structures of low salient

swell in sag

and salient

accounting for 45.3%

24.9% and 22.0% respectively.Vertically

about 61.0% of the proven oil reserves and 55.0% of the proven gas reserves are distributed in the Neogene.About 93.2% of the proven oil reserves and 85.0% of the proven gas reserves are distributed in the shallow to medium reservoirs with burial depth less than 3 000 m.The hydrocarbon distribution in Bohai Sea waters is the result of a series of geological processes

involving hydrocarbon source rock

depositional systems

structures

as well as fault systems.The hydrocarbons migrated in short distance and accumulated around the hydrocarbon kitchens.Factors such as favorable sedimentary facies belts

high-quality lithofacies

and favorable physical properties played important roles in the development of high-quality reserviors in Bohai Sea waters.The Tanlu fault and its induced faults controlled the formation and development of hydrocarbon kitchens

traps and carrier systems in the study area.