The structural features of the rocks of the Achimov Formation of the West Siberian basin, studied from well cores, well logs, and 3D seismic data, indicate that most of them were formed by hyperpycnal (extrabasinal) turbidite flows, rather than classical (intrabasinal) turbidite flows. Almost all sandy and silty-sandy rocks are deposits of extrabasinal turbidites the formation of which was directly related to the discharge of river flood waters into the sea basin. The following features indicate the hyperpycnal genesis of turbidites: the presence of plant detritus and large wood fragments; lack of a complete classical sequence of the Bouma cycle; channel systems cutting through the shelf edge, identified based on 3D seismic data. The amount of carbonaceous detritus and carbonaceous layers and lenses is minimal in the axial zone of turbidite channels and the proximal part of the lobes, gradually increasing towards their marginal parts, represented by thin-layered sandstones interbedded with layers of clayey siltstones and mudstones.