Sedimentary Evolution of Gravity Flow Disposition of Yinggehai Formation in Qiongdongnan Basin

Key words: 
• slump /
• turbidite channel /
• sedimentary characteristics /
• sedimentary evolution /
• Qiongdongnan Basin

Abstract: Qiongdonan Basin is one of China's important hydrocarbon and hydrate-bearing basin. The study of its sedimentary characteristic and deep water deposition system evolution plays a significance role to the future exploration. Based on the high precision 3D seismic data, we analysis the depositional system of the western of Ganquan Uplift in the deep area of Qiongdongnan Basin. Through the method of seismic attribute extraction and recognition, we distinguish the sedimentary characteristics of two different sedimentary bodies, including turbiditic channel and slump. The channel, influenced by the bottom flow, is parallel with the continental slope of South China Sea and combining with the asymmetric levee. Through seismic section interpretation, we can also distinguish the two sets of slide disposition. The bottom slide is a kind of normal disposition with several variable period. The top slide disposition, due to the injection of bottom flow, has a lower density and viscosity. Because of the decrease of the density and viscosity of water, these kinds of slide have wide influence range and significantly layered property. With the help of RMS-attribute slice and sedimentary reconstruction of Yinggehai Formation, we divide the evolution into three stages: the stage of sliding, the stage of erosion by bottom flow channel, and the stage of re-sliding.