Home – Home – Jornals – Chemistry for Sustainable Development 2025 number 2

Oil production from low-permeable reservoirs is an urgent and promising issue because of the depleted reserves of oil extracted using traditional procedures, both in Russia and abroad. The statistical analysis of porosity distribution in the sediments of the main oil and gas basins (OGB) of Russia is presented: the Volga-Ural, Timan-Pechora, North Caucasus and West Siberian. These basins have large reserves of hard-to-recover oil from complex formations with low porosity. Computer maps of the deposits with low-pressure reservoirs are presented. In the West Siberian basin, 15 deposits of this kind have been identified, 13 deposits in the Timan-Pechora basin, 63 in the North Caucasus, and the largest number of deposits is located in the Volga-Ural basin - 82. The great role of low-porosity rocks in the oil and gas potential of basins is shown, 80 % of the Russian reserves of low-porosity sediments are concentrated in the Volga-Ural basin. According to lithological characteristics, low-permeable reservoirs mainly belong to carbonate sediments, but the porosity of terrigenous rocks is higher, compared to carbonate deposits. The presence of reservoirs in various stratigraphic layers has been established, starting from the Cenozoic and ending with the Paleozoic, but most rocks belong to the Paleozoic age. The distribution of reservoirs with low porosity is analysed as the depths increase. It is shown that porosity decreases at great depths (over 5000 m) by a factor of 2-3, while the proportion of low-porosity sediments increases with depth, compared to medium-pored and highly porous rocks. In the future, at great depths, the role of low-permeable reservoirs as the sources of hard-to-recover oil will only increase.