• 责任者：Zhang Gongcheng (Research Institute ; CNOOC ; Beijing 100027 ; China) ; Xie Xiaojun
• 刊名：Acta Petrolei Sinica
• 出版年：2013
• 卷期：34(4)
• 关键词：油气勘探 ; petroleum exploration ; 含油气盆地 ; petroliferous basin ; 南海 ; South China Sea
• 页码：p.611-627
• 图表：illus., 5 tables, 41 refs.
• 分类号：1003
• issnNo：ISSN0253-2697
• isbnNo：CN11-2128/TE

     Since Late Mesozoic, the united South China Sea region has experienced at least two tectonic cycles of marginal seas, i.e. the cleav- age to convergence of the paleao-south China Sea, and the cleavage to convergence of the neo-south China Sea, which formed a couple of structural units, such as the northern continental margin of the South China Sea, the oceanic basin of the neo-South China Sea, the Nansha block, the residual oceanic basin of the palaeo-South China Sea, the northern continental margin of Borneo, and the western and eastern con- tinental margins of the South China Sea. The tectoic framework developed in the cleavage of the palaeo-South China Sea was afterwards trun- cated and reworked to form a new tectoic framework because of the difference in locations of the palaeo-South China Sea and the neo-South China Sea. The superimposition of these two cycles controls properties of these different units, types of overlying basins and geological condi- tions of hydrocarbons. The northern continental margin of the South China Sea was of a passive continental margin in both the cycles though its scale （including the Nansha block parting away during the second cycle） was larger in the first cycle than the present residual part of the first cycle, which, only as an intracontinental rift part, was superimposed by the transitional marine rift developed in the late cycle to form tensional basins. Source rocks of the early cycle dominated by semi-deep lake strata, are distributed offshore and mainly generate oil that ac- cumulate in nonmarine or marine facies, while those of the late cycle, composed of mainly transitional deltaic deposits and marine mudstones, are distributed infralittorally and generate oil that are reservoired in marine facies. The Nansha block used to be a rift basin that developed marine source rocks and was located at the northern continental margin of the South China Sea in the early cycle, afterwards it drifted south-ward for thousand kiometers and lay between the palaeo- and neo-oceanic basins, remaining in an under compensation status. During the late cycle it was compressed and reworked, its deposits are dominated by marine facies of the early cycle, with occurrences of marine source rocks and reservoirs. The southern continental margin of the palaeo-South China Sea used to he a passive continental margin during the early cycle but was reworked into an active continental margin during the late cycle. Stretched basins formed in the early cycle are superimposed by eom- pressional basins developed in the late cycle, and strata of the early cycle are deeply buried and of metamorphism, while strata deposited in the late cycle consist mainly of large-scale deltas and marine mudstones, with occurrences of both oil and gas in marine facies. The western conti- nental margin of the South China Sea was formed in an intracontinental environment during the early cycle, and then reworked into a transfor mational continental margin during the late cycle, where tenso-shear basins developed with restricted terrestrial strata deposited in the early cycle and transitional deltaic strata deposited mainly in the late cycle. This area has a high value of heat flow and is apt to generate gas. Oil- gas reservoirs such as diapirs, buried hills and reefs are well developed in this area. Presently the eastern continental margin of the South Chi- na Sea is subducting with the development of aecretionary wedge basins. The superimposition of the two different cycles leads to a great difference in exploration potential of different areas. The southern continental margin of the palaeo-South China Sea experienced extension and compression in the early and late cycles, respectively, resulting in the formation of large-scale basins, the richness of mature source rocks and enormous resources of hydrocarbons. Two suits of source rocks are well developed in rift basins of the northern and western South China Sea and they have generated an abundance of hydrocarbons. The Nansha block was located at the northern passive margin of the palaeo-South China Sea in the early cycle and restrained between the remnant oceanic basin of the palaeo-South China Sea and the oceanic basin of the neo- South China Sea. It contains well-developed structural straps due to regional compression and shows a great potential in petroleum resources. Presently, the degree of petroleum exploration is high in shallow water areas of the South China Sea, especially for structural traps and or- ganic reefs, with the exception of non-structural traps. However, the petroleum exploration in deepwater and ultra-deepwater areas of the South China Sea remains yet at an infant stage though some significant discoveries have been made. Hence, the exploration potential of the South China Sea is still considerably great in the future.