Undiscovered Oil and Gas of Russia's Volga-Ural and Timan-Pechora Basins

The two assessment units of the Volga-Ural Basin Province and the three of the Timan-Pechora Basin Province, Russia. USGS map.

The estimate

Using a geology-based assessment method, the U.S. Geological Survey estimated the undiscovered, technically recoverable conventional oil and gas of two Russian basin provinces, with fully risked means of:

Ranges run from F95 (a 95-percent chance of at least that much) to F5.

Two basins, one history

The Volga-Ural and Timan-Pechora provinces share a similar tectonic, structural and stratigraphic history, and similar petroleum systems.

• Rifting: in the Ordovician, Silurian and Devonian, several phases of rifting as the cratons of Eastern Europe and Siberia separated left a mosaic of rift basins, grabens, horsts and uplifts along the Eastern European craton's passive eastern margin.
• Platforms and shales: as rifting waned, subsidence and rising seas built extensive carbonate platforms on the horsts, while organic-rich shales settled in the deep basins between. Clastic sediments followed during regressions, mostly in the Carboniferous.
• The Urals: through the Carboniferous and into the Permian, the Uralian ocean closed, and the collision of the Eastern European craton with the Siberian terrane raised the 2,000-kilometer-long Uralian fold belt, with a foreland and foredeep beside it. Kilometers of sediment buried the source rocks deeply enough to generate oil in the foreland and gas in the foredeep during the Permian. Most rift structures were inverted — and they hold most of the two provinces' conventional oil and gas fields.
• Maturity: both basins are at a mature stage of exploration for conventional resources, especially oil in structural traps. What remains is mostly small fields and fields in stratigraphic traps. The assessment also estimates the part of the Timan-Pechora province north of the Arctic Circle.

The petroleum system

The USGS defined one Paleozoic Composite Total Petroleum System across both provinces, since several potential source rocks exist in the Paleozoic section — organic-rich marine shales of the Silurian, Devonian, Carboniferous and Permian. The main source in both basins is organic-rich shale of the Devonian Domanik Formation. In the geologic model, the Domanik and other sources were buried by Uralian clastics and generated oil and gas, which migrated into carbonate platform, slope and deep-water clastic reservoirs in structural traps in the foreland, and into clastic reservoirs in structural and stratigraphic traps in the foredeep. Most potential oil fields are expected in the foreland; most gas fields in the foredeep and fold belt.

The assessment's inputs are summarized in the fact sheet and in Schenk (2022).

Sources

Based on the USGS Volga-Ural Basin and Timan-Pechora Basin Provinces Assessment Team (Christopher J. Schenk and colleagues), "Assessment of Undiscovered Conventional Oil and Gas Resources of the Volga-Ural Basin and Timan-Pechora Basin Provinces of Russia, 2020," Fact Sheet 2022–3070, September 2022, U.S. Geological Survey; a work of the United States government in the public domain. The map and the unit-by-unit results are taken from the fact sheet's PDF.