The Subtle Reservoir Research Of The First Member Of Dainan Formation In Sanhe Sub-Sag Of Jinhu Depression

This paper make full use of logging data,core data,well test and analysis data to carried out the provenance analysis and depositional characteristics research of The First Member of DaiNan?E₂d₁?formation of SanHe sub-sag,points out the possible subtle trap type of research area,established the subtle reservoir accumulation model,and identified several subtle trap in favorable area.Through the study,acquired following main understanding:?1?The deposition of E₂d₁formation mainly controlled by LiuBao-Ling TangQiao low uplift in eastern and JianHu uplift in western,and the sediment from eastern provenance can spreaded to west in far range.?2?The study of sedimentary facies show that E₂d₁ of SanHe sub-sag mainly developed three type of facies:delta facies,braided river delta facies and lacustrine facies,there developed two delta system at the east and west of the sag.The figure of two delta system looks like leaf or finger.In the vertical direction,the delta system developed inheritable.The evalution character is that the west delta system shown as progradation,the east delta system shown as retrogradation1.?3?Based on the depositional analysis,reservoir research and structure analysis,points out that four type of subtle trap were developed in the research area,include fault-lithologic trap,sandstone updip pinchout trap,lens trap and stratigraphic onlap trap;Set up the gas and oil accumulation model of subtle trap of E₂d₁:FuNing formation provide oil source,channel sandstone of E₂d₁ was reservoir,source-related fault and sandstone provide migration pathway;Deep sag area of SanHe sub-sag is the most favorable area for the formation of subtle reservoirs.?4?In favorable area,relying on high accuracy 3D seismic data,carry out structure interpretation and various type of reservoir prediction,found many subtle trap and the exploratory well GaoX29A acquired commercial discovery.