| Based on the analysis of the Cenozoic plate activity around the South China Sea(SCS), it is considered that the tectonic evolution of the SCS is controlled by the interaction among the three plates of the Pacific, Eurasia and India, and can be divided into three stages: rifting stage(E), fault-depression transition stage(N11—N12) and regional subsidence stage (N13—present). The discovered oil and gas reservoirs in the SCS can be divided into three types: structural type, lithologic type and composite type. Futher, the structural type can be divided into anticline type, fault-anticline type and fault block (nose) type; the lithologic type can be divided into reef beach type and deepwater channel type; the composite type can be divided into structural-lithologic type and bedrock buried-hill type. It is considered that the three stages of tectonic evolution control the formation of different types of traps and reservoirs, thus controlling the distribution of three types of oil and gas reservoirs. Structural reservoirs are mainly distributed in the southern and northern sides of the SCS near the continental margin, most of which are oil fields; reef-beach reservoirs are distributed far from the continental margin, most of which are gas fields. In strike-slip fault basins in the west of SCS, not only structural reservoirs but also complex reservoirs developed. The structural and reef-beach reservoirs have the characteristics of forming early in north and late in south. In the west strike-slip basin, many composite oil and gas reservoirs developed, with structure-lithology being dominant in northwest, with the bedrock buried-hill being dominant in southwest, which developed early in the south than in the north. Deep-water channel reservoirs are concentrated in the Upper Miocene—Pliocene latest. |
