Fine Characterization of Braided River Reservoir Architecture from the Guantao Formation in the Nanpu2-1 Block,Bohai Bay Basin
[Objective]The sand body structure of a braided river reservoir and the spatial distribution of its seepage barrier are the key geological factors affecting the water injection development effect in the Nanpu2-1 block.[Meth-ods]This study comprehensively applies core,logging,and three-dimensional seismic data to conduct fine reservoir characterization based on the spatial distribution of level 4 architecture units in the braided river reservoir.[Results]According to the dense well pattern anatomy,the level 4 architecture units of three genetic types of braided bar,braided channel,and overflow in NgⅡ-6(Neogene Guantao Formation II oil group 6th sublayer)of the Nanpu2-1 block are identified,and three vertical superposition types(braided bar-braided bar superposition,braided channel-braided bar superposition,and overflow-braided bar superposition)and three lateral splicing types(braided bar downstream progradation overlapping splicing type,braided channel separated braided bar type,and braided bar dis-tributing braided channel type)are established.Using the root mean square amplitude and frequency division red-green-blue(RGB)fusion stratigraphic slicing technology,the plane distribution of level 4 architecture units from NgⅡ-6 in the Nanpu2-1 block is predicted,and the geometric shape,scale,and contact relationship between braid-ed bar reservoir unit and braided channel as seepage barrier are revealed.[Conclusion]The research provides a di-rect geological basis for the optimization and adjustment of oilfield water injection development scheme and improving oilfield development effect.