Sedimentology of lower section of third member of Shahejie Formation on western slope of Lijin Subsag, Dongying Sag, Bohai Bay Basin: a case study of Bin 648 area, Binnan Oil Field

The Binnan Oil Field tectonically belongs to the western slope of Lijin Subsag, Dongying Sag, Bohai Bay Basin. The Bin 648 area is an anticlinal fault oil reservoir (higher in the north and lower in the south) complicated by faulting. The lower section of the third member of Shahejie Formation is the main oil-bearing series and is in the development stage of medium-low water content and low oil production rate. Based on the standardized processing of logging data, the multi-well edit module of the Direct-Art software was used for stratum division and sand body contrast using the elevation vertical depth contrast pattern. Finally, the lower section of the third member of Shahejie Formation was divided into five sand groups and eleven thin layers. The grain-size cumulative probability curves and C-M chart of well Bin 648 showed coarse to medium size and high density turbidite sediment characteristics. The lower section of the third member of Shahejie Formation is dominated by fan delta front subfacies and pre-fan delta subfacies, including submerged distributary channel microfacies, tributary bay microfacies, channel bar microfacies, frontal sheet sand microfacies and pre-fan delta lacustrine mudstone microfacies. The favorable facies belt for oil and gas reservoirs are the submerged distributary channel microfacies and channel bar microfacies.