CHARACTERISTICS OF GEOLOGIC STRUCTURES OF THE NORTH YELLOW SEA BASIN: IMPLICATIONS FOR PETROLEUM EXPLORATIONS

On the basis of latest oil exploration data from the North Yellow Sea basin and together with regional geologic research results,the authors have analyzed geologic structures of the basin at the angles of basement structures,geologic structures and main tectonic types.It is suggested that the basin has its development based upon Pre-Mesozoic crystalline basement and undergoes three large subsidence processes represented by three structural layers,and as a result of that,three basic tectonic types(fault,fold and buried hill)are formed in the basin.These structural characteristics provide good conditions for generation,migration and accumulation of oil in the basin.Especially the lower structural layer of late Jurassic-early Cretaceous is the best hydrocarbon-producing layer that has good trap development conditions and whose reworking afterwards favors the generation and accumulation of oil and thus should be the major exploration target layer in the North Yellow Sea basin.