HYDROCARBON ACCUMULATION CHARACTERS AND EXPLORATION PROSPECTS OF DEEP-SEATED OIL-GAS RESERVOIRS IN BOHAI BAY BASIN

Buried hills, igneous rocks and clastic rocks are the three main types of reservoirs and oil-gas pools in the deep part of the Bohai Bay Basin. According to the main control factors, five hydrocarbon accumulation models were obtained.They are the dissolved pore-crack reservoir in the weathering crust under the source rock, the inner crack reservoir in buried hills under the source rock, the igneous crack reservoir within the source rock, overpressured sandstone pore-crack reservoir with the source rock and sandstone/gravel crack reservoir beyond the source rock, respectively. The distribution of the buried hill reservoirs is extensive, and igneous rock reservoirs limited. Overpressure sandstone pore-crack reservoirs within the source rock mainly occur in the middle and east part of the Bohai Bay Basin. Sandstone/gravel cracks outside the source rock reservoirs are less in the Bohai Bay Basin.According to this study, the buried hill and under-compaction clastic rock reservoirs are the realistic exploration targets, but igneous reservoirs should not be neglected due to its high potential.