近年来随着琼东南盆地深水区中央峡谷气田群的发现,水道砂体作为南海北部油气勘探的一种重要储层类型得到了更多的重视.基于琼东南盆地南部深水区三维地震数据以及地层切片、属性提取等地震技术,发现中新世水道频繁发育.根据水道延展方向、平面分布及下切形态等特点,中新统水道演化大致可分为3个阶段:早中新世早—中期,NE—SW向限制性水道集中发育,地震剖面上表现为中—强振幅,多呈"V"形下切;早中新世晚期—中中新世,SE—NW向顺直水道广泛发育,呈短轴状及"V"、"U"形下切;晚中新世局部发育较大规模的SE—NW向水道,呈"U"形下切.中新统水道的发育,受到古地貌和相对海平面变化的控制:早中新世,水道在海底负地形单元内集中发育;中中新世相对海平面大规模下降,水道广泛发育于台地前缘斜坡;晚中新世相对海平面快速上升,仅发育少量但规模较大的水道.

Deep-water channel is getting more attention as one of the important reservoirs for oil and gas exploration in the northern South China Sea with the discovery of Central Cannon gas field group. This paper describes the features of the Miocene channel system in the south of Qiongdongnan Basin and analyzes the channel evolution based on 3D seismic data and the technologies of strata slice and seismic attribute extraction. Based on extending direction, horizontal distribution and cutting shape of the channel, the evolution of Miocene channel system is divided into three stages: confined channel system with middle-high amplitude and V-shape cutting down developed in the early-middle period of the Early Miocene, extending in NE-SW direction; straight channel system with V-shape or U-shape developed widely in the late of the Early Miocene to Middle Miocene, extending in SE-NW direction; in the Late Miocene, great channel with U-shape cutting down developed locally in the northeast of the study area, extending in SE-NW direction. The development of Miocene channel system was affected by paleogeomorphology and sea level change. In the Early Miocene, confined channel system developed in narrow and low terrains around west part of Xisha carbonate platform. In the Middle Miocene, straight platform slope channels developed with relative sea level dropping. In the Late Miocene, only a few great channels developed with relative sea level fast-rising.