The article considers a method for evaluating the optimal distance between wells based on CRM (capacitance-resistive models) in the case of Achimov formation. Achimov formation is characterized by a complex geological structure (low permeability, the presence of isolated interlayers, high heterogeneity). These properties are the reason for the low sweep efficiency. At the same time, design solutions for medium productive sediments of the Cretaceous and Jurassic complex are not applicable for Achimov formation development. Substantiating of the pattern, as a rule, is based on carrying out various hydrodynamic calculations. This approach for determining the drainage radius often leads to the selection of high spacing grid because simulation model does not take into account the actual discontinuity and heterogeneity of the reservoir. Using an alternative method to determine the size of the drainage area such as hydrodynamical study in low permeability conditions leads to the need for well shutoff for a long time that causes mining loss. In this study the CRM based on material balance equation is used to determine the optimal inter-well distance. The method allows to estimate the drained pore volume based on history match to well performance. The optimal distance between the wells is determined from the condition of alignment of the outer boundaries of the drainage zone. In this work, the method is approved on the Achimov formation of the Kogalymskoe field. Evaluation of the drained reservoir volumes was carried out, and the optimal pattern was calculated. This distance is also a significant parameter in assessing the potential impact of injection. The performed analysis allows to estimate the optimal inter-well distance, significantly reducing the time expenditures in comparison with the use of hydrodynamic calculations.