Abstract
The article discusses methods for assessing and forecasting residual recoverable oil reserves at the late stages of field development using displacement characteristics. The purpose of the study is to determine the effectiveness of analytical methods for evaluating the involvement of residual reserves in development under the conditions of an established operation system of mature fields. The study employs the methods of Nazarov–Sipachev, Maksimov, Sazonov, and Kambarov, as well as the relationships between cumulative production and the logarithm of the water-oil ratio and between specific production and cumulative production. Experimental studies of relative phase permeability, oil displacement coefficients by water, and capillary characteristics of rocks were conducted. The obtained results demonstrated the possibility of refining potentially recoverable reserves and increasing the oil recovery factor for the studied objects. It was established that the application of displacement characteristics makes it possible to identify undrained zones and justify measures aimed at improving the efficiency of field development. The scientific novelty of the study lies in the integrated application of analytical methods for forecasting residual reserves while considering the current state of field development. The practical significance of the work consists in the possibility of using the proposed approach for planning geological and technical measures and optimizing the development system of mature oil fields.