Article is dedicated to geologic architecture features of reservoirs № 4 and № 5 located in the east of Bakhilov field, and to special nature of developing the above accumulations. The authors made integrated analysis of seismic materials, field log and core data, described depositional environments, identified facies elements. Conclusions were drawn on paleogeographic features affecting field development process. It was suggested that selective approach to desig ning separate reservoir blocks development system was needed.