【摘要】 南海是中国唯一发育有洋壳的边缘海,是世界四大海洋油气聚集中心之一。油气勘探表明,南海的油气田分布在北部、西部和南部陆缘沉积盆地内,而大中型油气田集中分布在西部海域盆地中,自北而南有莺歌海—琼东南盆地、万安盆地、湄公盆地、曾母盆地和文莱—沙巴盆地,且以含气为主,含油次之。此外,这一区域深水区还存在多个潜在的大型含油气盆地。研究发现,南海的油气分布与深部岩石圈结构有密切关系。在构造上,南海的含油气盆地位于岩石圈块体边缘或之上,受控于大型岩石圈断裂的发育与演化。在油气富集的盆地中,莫霍面显著凸起,与盆地基底形成镜像,地壳厚度最薄处仅数千米厚,热流值明显较周围地区高,热岩石圈厚度大大减薄。地震层析成像结果反映,这些盆地深部发育一条规模宏大的北西向上地幔隆起带,自红河口向东南穿越南海西部海盆,一直延伸到婆罗州东北部地区,在宏观上控制了南海的油气分布与富集。更多还原

【Abstract】 The South China Sea is one of the four major marine petroleum accumulation centers in the world and also China’s only marginal sea where oceanic crust is developed. Petroleum exploration shows that petroleum fields in the South China Sea are distributed in the northern, western and southern continental-margin sedimentary basins and that large- and medium-sized petroleum fields are concentrated in basins of the western sea area. These basins are from north to south the Yinggehai-Qiongdongnan basin, Wan’an basin, Meigong basin, Zengmu basin and Brunei-Sabah basin. They contain mainly gas and subordinately oil. Moreover, there are several large potential petroleum-bearing basins in deep-water areas of the region. Further studies indicate that the petroleum distribution of the South China Sea has close relationship with the deep lithospheric structure. Tectonically, the petroleum-bearing basins in the South China Sea are located on or at the edges of the lithospheric blocks, controlled by the development and evolution of large lithospheric faults. The Moho surfaces in these basins are uplifted remarkably and form mirror images of the basin basements. The crust of the basins is only several kilometers thick at the thinnest site, where the heat flow values are notably higher than those in their surrounding areas. The thickness of the thermal lithosphere is reduced greatly. Seismic topographic imaging shows that at depths of these basins an enormous NW-trending uplift zone of the upper mantle extends from the Red River Mouth southeastward through the southwest sub-basin of the South China Sea to the northeast of Borneo, which macroscopically controls the petroleum distribution and accumulation of the South China Sea.更多还原