中文摘要：

南海北部陆缘发育潜在油气储层,也是当前南海深水油气勘探的热点区域。然而深水区由于缺少钻井资料,地震资料就成为最主要的研究手段。基于大面积高分辨率三维地震数据,通过剖面地震相分析、三维地震数据体切片、层间属性计算分析、三维可视化等地震解释技术,在白云凹陷晚新生代地层中识别出两套深水水道沉积体系,分别为早中新世晚期发育早期水道体系和自中中新世发育至今的后期水道体系。早期水道体系为单条主干水道为主要沉积区域的沉积体系,识别出水道底部充填、堤岸以及侧壁滑塌等沉积微相;根据地震相变化,发现水道演化分为两个期次：第一期水道下切侵蚀较强,具有＂V＂形谷底,第二期下切相对较弱,具有＂U＂形谷底。后期水道体系为一系列彼此平行并置,并近于垂直横切陆坡的水道体系,演化至现今海底;可以识别出底部滞留、侧壁滑塌以及侧壁加积等沉积类型;后期水道体系共发育4个期次,发育时间分别为13.8～12.5、12.5～10.5、10.5～5.5和5.5～0Ma。白云凹陷晚新生代水道体系表现出对沉积物较好分异和筛选,具有重要的油气资源效应：早期水道体系与上覆正常半深水泥质沉积组成良好储盖组合;后期水道体系发育至今,对于形成高富集度的砂岩型水合物储层具有重要意义。

英文摘要：

The Northern continental margin of South China Sea bears great potential of oil and gas resources,and has been the hotspots of deep-water petroleum exploration for decades.Based on the highresolution 3Dseismic data from the region,we used in this paper a series of seismic sedimentology techniques,including seismic facies analysis,3Dseismic slice technique,attribute computation between horizons and 3Dvisualization technology for integrated researches.Two sets of deep-water channel systems in the Late Cenozoic of the Baiyun Sagare are recognized.They are the early channel system formed in the Early Middle Miocene and the late channel system formed later since the middle Middle Miocene.The early channel system is a point-source single channel filled with channel axis infilling,levee and mass transportation deposits.According to seismic facies,the early channel system consists of two sets of sediments：1）the sediments of stage I is characterized by strong downward erosion and＂V＂shaped bottom boundary and2）the sediments of stage II characterized by weak erosion and ＂U＂shaped bottom boundary.The late channel system is composed of series of sub-parallel channels along the slope formed up to the present.The system consists of the sediments formed in four stages：stage I（13.8-12.5Ma）,stage II（12.5-10.5Ma）,stage III（10.5-5.5Ma）and stage IV（5.5-0Ma）.The channel system in the Baiyun Sag shows good depositional differentiation and has big potential for oil exploration.The early channel system with upper deepwater deposits could form a reservoir-seal assemblage in the deep-water area.And the late channel system is of significance for the formation of enriched gas hydrate reservoirs.