Seismic Sendimentary Study Of An Off-shore River-dominated Shallow-water Delta: A Case Study From The Upper Member 3 Paleogene Shahejie Formation,kenli10-1 Oilfield,Bohai Bay Basin

Located in north of Laizhouwan Depress of Bohai Bay Basin,the Upper Member 3 Paleogene Shahejie formation of Kenli 10-1 oil field was believed as a river-dominated shallow-water delta reservoir.The purpose of this paper is to characterize the reservoir under the guidance of seismic sendimentary study of Kenli10-1 Oilfield with the new acquired 150km2 of high resolution 3D seismic data combined with limited well logs and core data,which is of great importance to calculate the original volume of hydrocarbon,to make optimal development strategies of the offshore oilfield.Core and well log data were used to study the stratigraphic architecture and depositional settings of the study area.Member 3 Paleogene Shahejie Formation was subdivided into 10 sub-zones according to depositional cycles and each got a thickness of 10-15 meters.Five main lithofacies were identified by core observation and well log analysis and they were interpreted as river-dominated shallow water delta complexities.Single net sandstones ranged from 3-6 meters and were determined as distributary channel and distributary mouth-bar facies,which could stack vertically to thicknesses as much as 15-20 meters and made the most favorable pay formation of the oilfield.Then strata slices of seismic attributes picked from the 3D seismic volume were utilized to delineate the shallow water delta lobes and detect the individual distributary channels and mouth bars distribution of between and beyond wells,which demonstrated that the methodology presented here was suitable for the facies architecture characterization of offshore thin-bedded shallow-water delta reservoirs.