南海准被动陆缘深水油气与水合物共生意义

THE GEOLOGICAL SIGNIFICANCE OF THE PARAGENETIC ASSOCIATION OF HYDROCARBON AND HYDRATE IN QUASI-PASSIVE MARGIN THE NORTHERN SOUTH CHINA SEA

南海北部准被动陆缘深水区处在欧亚、印-澳和太平洋-菲律宾三大板块相互作用之特殊大地构造位置,具有被动大陆边缘拉张裂陷的基本属性和典型断拗双层或三层盆地结构及沉积充填特征,与相邻的北部陆架浅水区一样具备基本油气成藏地质条件。南海北部准被动陆缘深水盆地油气运聚成藏地质条件与世界典型被动陆缘盆地深水油气富集区基本类似,但亦存在一定的差异和特殊性。南海北部深水油气运聚成藏及其空间分布与天然气水合物具有纵向上的共生组合关系及烃源供给上的成因联系,其油气地质意义在于其浅层油气及海底水合物显示可以指示深部油气藏的存在或作为深部油气藏勘探的指向和示踪,而这种空间上的共生叠置关系,亦拓宽了资源勘探领域,扩大了其资源规模及潜力。

The deep water district of Quasi-passive margin of the northern South China Sea is located in the place where the three major tectonic plates(Europe and Asia,India-Australia and the Pacific-the Philippines) interact.It has the basic properties and typical double-layer or three-layer structure and sedimentary character of the passive continental margin extensional rift and it has the basic geological conditions for reservoir forming like the adjacent shallow water area of the northern continental shelf.The geological conditions for oil and gas migration and accumulation in the deep-water basin of quasi-passive continental margin in northern South China Sea are similar to some typical passive continental margins in deep-water oil and gas rich regions of the world,but there are also some differences between them.The oil and gas migration and accumulation in northern South China Sea and the spatial distribution of gas hydrate have a paragenetic association in the vertical and a source supply relation on genesis,and the important oil and gas geological significance is that the appearance of shallow oil and gas and the submarine hydrate can indicate the existence of deep oil and gas reservoirs or serve as a pointing and tracing of deep petroleum exploration.Besides,the paragenetic association in space also broadens the fields of resource exploration and greatly expands the size and potential of its resources.