COMPREHENSIVE METHOD OF LOCALIZATION OF RESIDUAL RECOVERABLE OIL RESERVES AT A LATE STAGE OF DEVELOPMENT OF FIELD DEPOSIT BASED ON THE EFFICIENCY OF THE CARRIED OUT GEOLOGICAL AND TECHNICAL MEASURES

At the beginning of 2025, more than half of the oil reserves in Russia's fields are classified as hard-to-recover, and by 2030 this proportion may grow to 70 %. As oil fields are developed, the share of conventional reserves continues to decline. To ensure the rational development of the remaining resources, which are characterized by increased extraction complexity, the implementation of innovative technological solutions and the improvement of extraction methods are required. For the effective extraction of residual recoverable reserves (RRR) of oil, it is necessary to identify and accurately determine their spatial distribution across blocks and reservoirs. The accuracy of determining the localization of RRR impacts the success of geological and technical measures (GTM), and consequently, it may influence the achievement of the projected oil recovery factor (ORF). This article describes a comprehensive methodology for localizing RRR, which enables the identification of prospective zones and the selection of appropriate geological and technical measures. The proposed methodology includes the verification of coefficients comprising the ORF formula, the analysis of GTM, and the creation of a «GTM desirability map» to identify prospective areas with residual reserves. Additionally, it optimizes the field development process and reduces labor costs for specialists in selecting GTM. The key aspects of the methodology are described in detail, taking into account its practical applicability and accessibility for professionals in the oil and gas industry. The application of this methodology has resulted in the verification of the ORF and the clustering of reserves in one of the fields in Western Siberia. Furthermore, recommendations have been developed for conducting targeted geological and technical measures, optimizing the reservoir pressure maintenance system, and confirm or decommission oil reserves.