The rocks of the bazhenov formation are hard to recover reserves. One of the problems related to the calculation of reserves of hydrocarbons confined to deposits of the bazhenov formation is the lack of a comprehensive approach to the detailed study of the properties of these rocks. Challenge of industry is to develop an approach to the definition of the parameters needed for the assessment and calculation of oil and gas deposits related to deposits of the bazhenovfFormation. In this paper, the authors propose a multiscale approach to the study of the bazhenov formation samples, which allows us to characterize the different levels of the void space, structure and composition. The aim of the study was to determine the possibilities of modern bulk multiscale microscopy for solving problems on the properties of bazhenov formation samples and improve the accuracy of input data for reservoir properties modeling. To achieve this goal it was necessary to solve the following problems:• Clarify and complement the structural information obtained by traditional methods (X-ray microtomography), by mineral composition and porosity of the core in the micron and submicron scale.• Assess the reservoir rock properties in a wide range of scales with division of different types of porosity. The work served as a multiscale assessment process for bazhenov formation samples.