Geology exploration and reserves

Total number of fields is 122 (according to the state balance of reserves as of 01.01.2023).

The Company's assets are divided into the following groups according to the territorial and operation basis:

• West Siberia
• Volga
• Central Siberia

Oil and gas potential of the Volga group fields is associated with terrigenous and carbonate rocks of the Middle-Lower Carboniferous and Devonian, while in the West Siberian and Central Siberian regions - with deposits of the Upper Jurassic and Neocomian.

The prospects for the discovery of new oil and gas deposits, as well as the expansion of the oil-bearing areas of previous discoveries, are associated with a strategy for the stable implementation of the exploration program with a focus on the detailed high-quality CDP-2D/3D seismic surveys, as well as successful prospecting, appraisal, and exploration drilling.

At the same time, in recent years, hard-to-recover and unconventional reserves have become the main directions for replenishing the portfolio of reserves in the medium term. The growth of competencies in the field of studying and industrial development of hard-to-recover reserves, the analysis of ongoing works and generalization of the results of retrospective exploration allow to quickly rank projects in the Company, identify the most promising areas of development (Verkhne-Shapshinskoye, Tagrinskoye, Vostochno-Kamennoye, Zapadno-Varyoganskoye fields).

Since 2017, based on the results of an integrated methodological approach to the study of productive deposits of the Verkhne-Shapshinskoye field, the Company continues to actively develop the deposits of the Achimov formation. In general, since 2017, the Verkhne-Shapshinskoye field Achimov deposits reserves have added to more than 40 million tons of oil.

The implementation of the development drilling program at the Tagrinsky licensed area has confirmed the high efficiency of the ongoing exploration work and allows, in real time, to update the geological model of the Achimov deposits. The total changes in the reserves of the Tagrinskoye field for 2022 amounted to 12.9 million tons of oil. The main increase in oil reserves is associated with the Tagrinsky license area expansion to include hydrocarbon reserves located in the unallocated subsoil fund.

Implementation of the production drilling and exploration program in 2022 resulted in no changes in reserves.

In 2021, the Company acquired the right to conduct prospecting and appraisal work at several licensed areas in Khanty-Mansi Autonomous Okrug-Yugra.

In order to annually replenish the mineral resource base, the Company plans to continue pursuing the geological exploration policy based on:

• prospecting and exploration of new hydrocarbon deposits in oil and gas prospective horizons through prospecting and appraisal and exploration drilling, as well as advance production drilling;
• improving the efficiency of prospecting, appraisal, and exploratory drilling by improving the quality of CDP-2D and 3D seismic surveys, which makes it possible to study in detail complex hydrocarbon traps, including in deep-seated complexes represented by hard-to-recover reserves and unconventional reservoirs;
• expanding the boundaries of oil and gas potential of already discovered deposits; acquisition of potentially promising new subsoil areas based on geological, technical, and economic assessments.