Based on the 3D seismic data, taking into account the drilling results, on the example of one of Rosneft’s licensed areas within the Nepa-Botuoba anteclise, a general description of the composition and structure of the heterogeneous foundation and a detailed description of its surface are given. This surface is a local strip erosion form of pre-Vendian glacial-exaration paleorelief which, along with the protrusions of the foundation, determine the formation of facies heterogeneities in the basal sand deposits of the Nepa Vendian formation. The analysis of the probable features of the continental and coastal marine sediment accumulation in the geomorphological conditions of this relief is carried out. For the reconstruction of the paleorelief of the territory of a complex seismic-geological structure, the we used a map of the thicknesses of the Nepa Vendian Formation (data of 3D CDP method and drilling); slice sedimentation amplitude cube; and slice of spectral decomposition at the level of basal deposits of the Nepa Formation. General information on glacioperiods in the history interval of the Earth of 723-555 Ma and their manifestation within the southern part of the Siberian Platform is presented. Attention is drawn to the need to use in facies analysis the assumption that it was the melting of the vast glacial carapace that caused (the source of water mass) rapid transgression of the Nepa marine sedimentation basin. The example of a core sample from one of the wells illustrates the detection of tillites occurring on the surface of the foundation. It has been suggested that they are safe only under certain conditions. For deposits of the Nepa formation, taking into account all the data available to date, a facies scheme has been constructed that allows predicting reservoir distribution zones and is recommended for use in setting up exploratory and appraisal drilling.
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