Undiscovered Oil and Gas in the Central European Basin's Paleozoic Rocks

As part of its National and Global Petroleum Assessment, the U.S. Geological Survey (USGS) used a geology-based method to estimate the undiscovered, technically recoverable conventional oil and gas in the Paleozoic total petroleum systems of the Central European Basin System, which spans from Poland west to the United Kingdom and from Scandinavia south to Germany. The mean estimates are 278 million barrels of oil and 25.7 trillion cubic feet of gas.

The basin system is a stack of superimposed basins of different sizes and origins, the product of complex deformation that began in the Devonian. Seventy years of intensive exploration have found more than 250 trillion cubic feet of gas sourced from Carboniferous rocks, while discovered oil — about 1 billion barrels — is minor by comparison. The study asks how much conventional oil and gas remains, given what is known about how it is trapped.

Figure 1. The seven conventional assessment units in the Paleozoic total petroleum systems of the Central European Basin System. Base map from the U.S. Department of the Interior, National Park Service. Credit: U.S. Geological Survey.

Three petroleum systems

Carboniferous. Four assessment units: the Anglo-Dutch Basin, Northwest German Basin, Northeast German Basin and Mid North Sea High, all for gas. The main source rocks are Westphalian coals, or older Carboniferous coals in the Mid North Sea High. The gas migrated into Carboniferous fluvial-deltaic sandstones, eolian sandstones of the Permian Rotliegend Group, and carbonate reservoirs of the Permian Zechstein Group, mostly in salt-influenced structural traps sealed by evaporites.

Permian. Oil and gas generated mainly from the Permian Kupferschiefer Shale and equivalent organic-rich shales in the Northeast German Basin.

Paleozoic Composite. Gas from the organic-rich Cambrian–Lower Ordovician Alum Shale and gas held in lower Paleozoic reservoirs and structures in the Norwegian-Danish Basin, plus oil and gas from Paleozoic source rocks in the Polish Trough — where, given its history of uplift and erosion, oil and gas may not have been preserved.

Results

Fully risked mean estimates by assessment unit:

The totals are 278 million barrels of oil (F95–F5 range 173 to 410), 25,692 billion cubic feet of gas (15,158 to 40,027) and 227 million barrels of natural gas liquids (122 to 381); F95 means a 95 percent chance of at least that amount. About 70 percent of the undiscovered conventional gas is estimated to lie in the Carboniferous system.

Sources

Based on "Assessment of Undiscovered Conventional Oil and Gas Resources in Paleozoic Total Petroleum Systems of the Central European Basin System, 2019," by Christopher J. Schenk and others, U.S. Geological Survey Fact Sheet 2022–3066 (September 2022), published by the U.S. Geological Survey; rewritten in hubnx's own words.

• The imported page held only fragments of the fact sheet's tables; the text, map and results come from its PDF: https://pubs.usgs.gov/fs/2022/3066/fs20223066.pdf
• The map is shown without its legend, whose colours do not match the locations of the units named in the text (the colour given for the Northeast German Basin outlines an area reaching into Norway).
• Input data are in Schenk (2022), a USGS data release.