The gas-bearing areas in Poland are located on the northeast flank of the Carpathian Mountains, a region which extends geologically into Roumania. There are three belts in this province. About 100 oil-producing areas are scattered about in the two western belts, many of which also produce gas either with oil from common reservoir rocks or without oil from reservoir rocks above the oil-bearing series.

Rocks of Cretaceous and Tertiary (Eocene) age produce oil and gas in the western ("Median") belt. The Siary field produces gas and oil from rocks of Cretaceous age; Sekowa from Eocene and Cretaceous formations; and Potok from the Eocene. But the Sadkowa-Bialkowka-Brzezowka-Mecinka-Jaszczew fields (Jaslo district) produce only gas from rocks of Eocene age.

The central belt ("Marginal") produces oil and gas from rocks of Tertiary (Oligocene and Eocene) and Cretaceous ages; notably in the Boryslaw, Tustanowice, and Mraznica fields. Of these Mraznica ranks first.

The eastern belt ("sub-Carpathian") produces gas only from reservoirs in the upper part of the Miocene series at Daszawa and Kalusz. Wells have not been drilled deep enough to encounter rocks of Oligocene, Eocene, and Cretaceous age that are oil- and gas-bearing in the two western belts.

Poland is primarily an oil-producing state. Natural gas has been produced in the Carpathian region of Poland since 1912. Most of the gas produced prior to 1916 was wasted to the atmosphere, but since 1916 increasing amounts have been used for fuel purposes. The longest gas pipe line extends from the Daszawa field to the city of Lwow, a distance of 100 kilometers (about 62 miles).