琼东南盆地深层渐新统陵水组是南海海域下一步勘探的重点。基于岩心、测录井和三维地震资料，系统解剖了琼东南盆地宝岛凹陷北部陵水组沉积特征，明确陵水组可细分为2个三级层序，其中陵三段沉积为一个完整的三级层序，发育低位、海侵和高位体系域。控凹的F12断层差异活动形成的断层同向转换带以及转换斜坡控制着神狐隆起和海南隆起物源的注入，并控制了陵三段规模各异的西、东多支大型辨状河三角洲群的发育。断阶带在低位晚期和高位期主要发育辫状河三角洲前缘水下分流河道沉积，砂体厚度大，粒度较粗，分选较好，物性较好，为优质储层发育层段。由此建立宝岛凹陷北部断阶带陵三段深水盆地多级断裂控物源，转换断阶控砂体展布的发育模式。陵三段大型三角洲前缘水下分流河道优质储集体直接覆盖于崖城组烃源岩之上，与沟通烃源岩的断裂形成有利输导体系，又被后期拗陷期沉积的厚层海侵浅海泥岩覆盖，形成的优质储盖组合和输导体系是形成宝岛凹陷大型气田的关键。

Qiongdongnan Basin, a passive continental deep-water basin in the north of the South China Sea, is an important natural gas base in China. The deep Oligocene Lingshui Formation in Qiongdongnan Basin represent a primary target for forthcoming exploration in the South China Sea, however, due to limited exploration efforts, the sedimentary system of the Lingshui Formation remains inadequately characterized. Based on core, logging and 3D seismic data, the sedimentary characteristics of Lingshui Formation in northern slope of Baodao Sag, Qiongdongnan Basin are systematically dissected. It is clear that Lingshui Formation can be subdivided into two third-order sequences. The sedimentation of the 3rd member of Lingshui Formation is a complete three-order sequence with low, transgressive and high system domains. Under the control of the fault co directional transition zone and transition slope formed by the differential activity of F12 fault, several large differentiated river delta groups of different scales in the west and east are developed in the 3rd member of Lingshui Formation. The fault step zone mainly developed the underwater distributary channel of braided river delta front in the late low and high system tracts, and it is a high-quality reservoir development interval with the thickness of sand body being large, the particle size being coarser, the separation being better, and the physical property being better. Therefore, the development model of multistage fault-controlled material source and transition fault-controlled sand body distribution of the 3rd member of Lingshui Formation in the northern fault step zone of Baodao Sag is established. The high quality reservoir of large-scale delta distributary channel of the 3rd member of Lingshui Formation directly covers the source rock of Yacheng Formation and forms a favorable transport system with source rock-linked fault. And it is covered by thick transgressive shallow-sea mudstone deposited in late depression period. High-quality reservoer-cap combination and transport system are the key to forming large gas fields in Baodao Sag, and are worth of more attention in the future exploration.