Lower Paleozoic of Baltic Area

Thomas M. Haselton, Finn Surlyk

The Baltic Sea offers a new and exciting petroleum play in northwestern Europe. The Kaliningrad province in the Soviet Union, which borders the Baltic Sea to the east, contains an estimated 3.5 billion bbl of recoverable oil from lower Paleozoic sandstones. To the south, in Poland, oil and gas fields are present along a trend that projects offshore into the Baltic. Two recent Petrobaltic wells in the southern Baltic have tested hydrocarbons from lower Paleozoic sandstones. Minor production comes from Ordovician reefs on the Swedish island of Gotland in the western Baltic.

The Baltic synclise, which began subsiding in the late Precambrian, is a depression in the East European platform. Strata dip gently to the south where the Baltic Synclise terminates against a structurally complex border zone. Depth to the metamorphosed Precambrian basement is up to 4,000 m. Overlying basement is 200-300 m of upper Precambrian arkosic sandstone. The Lower Cambrian consists of shallow marine quartzites. During Middle and Late Cambrian, restricted circulation resulted in anoxic conditions and the deposition of Alum shale. The Lower Ordovician consists of quartzites and shale. The Upper Ordovician includes sandstones and algal reefs. The Silurian contains marginal carbonates and shales.

For the last 25 years, exploration in northwest Europe has concentrated on well-known Permian sandstone, Jurassic sandstone, and Cretaceous chalk plays. Extrapolation of trends known and exploited in eastern Europe could open an entirely new oil province in the lower Paleozoic in the Baltic.

AAPG Search and Discovery Article #91030©1988 AAPG Annual Convention, Houston, Texas, 20-23 March 1988.