Hydrocarbon accumulation in the shallow reservoirs of the Bohai Bay Basin:a case study of the Huanghekou Sag

As one of the petroliferous sags of Bohai Bay Basin,Huanghekou sag is abundant in shallow faults resulted from neotectonic movement.An analysis of the factors controlling hydrocarbon accumulation in the sag based on the abundant exploration data shows that these shallow faults play a key role in controlling hydrocarbon accumulation in the shallow reservoirs.Through the study on the fault combinations and the reservoirs under their control,we recognized three types of fault combinations and the corresponding hydrocarbon accumulation models. Moreover,we also identified the primary exploration targets for these fault combinations.For the 'X' -type fault combination,fault block reservoirs featuring in long hydrocarbon-bearing interval and large scale are the primary targets.For the ' cabbage' -type fault combination,the core and inner fault blocks are the primary targets.For the 'Y' -type fault combination,the structural high near the main fault usually are the primary targets.