General information and occurrence
In Poland, in 2019, there were 87 crude oil fields documented, including 29 fields situated in the Carpathian Mts., 12 on the Carpathian Foreland (in the Carpathian Foredeep), 44 within the Polish Lowlands and 2 in the Polish economic zone of the Baltic Sea. The oil fields occurring in the Carpathian Mts. and Carpathian Foreland have had a long history as this is the area of the world's oldest crude oil mining. However, nowadays these fields are almost depleted. Currently, the Polish oil fields of the largest economic importance are situated in the Polish Lowlands. In 2019, the exploitable resources of the fields located in this region accounted for 65.7% and the resources of the fields within the Polish economic zone of the Baltic Sea for 27.7% of the domestic crude oil resources in Poland. Resources of the Carpathian Foreland and the Carpathian Mts. are of a subordinate role (accounting for 3.6% and 3.0% of domestic resources, respectively).
On the Polish Lowlands, the documented oil fields are related to traps in the Permian, Carboniferous and Cambrian rocks. The oils are of the medium paraffin type, with the paraffin content ranging from 4.3% to 7.4%, the sulfur content slightly above 1% and the density withinthe range of 0.857 g/cm3 - 0.870 g/cm3. The majority of these fields are of the massive type, with a passive role of underlying water and with a gas cap expansion drive. The largest in Poland is BMB field (the short for a town name Barnówko-Mostno-Buszewo) located near the city of Gorzów Wielkopolski. Its resources of crude oil were found to be twice larger than the total domestic resources before its discovery. Other oil fields with significant resources occurring in this region include: Lubiatów, Grotów and Cychry.
In the Carpathian Mts., crude oil fields occur in several tectonic units, but mostly in the Silesian unit. The oil fields are mainly of the structural type, more rarely of the structural-lithological type, mainly of the laminar type with surrounding water. The production is initially driven by the expansion of natural gas dissolved in oil and subsequently by a gravity driven drainage.
Carpathian crude oil fields are mainly of the oil-gas type. The crude oil density ranges from 0.750 g/cm3 to 0.943 g/cm3 and the crude oil is allocated under sulfur-free type. The paraffin content varies from 3.5% to 7%. The resources of Carpathian oil fields are generally minor, depending on a size and a character of the structures which they are occurring in. The resources of the Carpathian fields have been significantly exhausted in the result of many years of exploitation.
In the Carpathian Foredeep oil fields are related to traps in Miocene rocks, in Mesozoic sedimentary rocks of the platform type (mainly within Jurassic carbonate rocks, rarely within Cretaceous sandstones), usually overlain by the impermeable Miocene clayey sediments. Most of these fields are of a layer type with stratigraphic, lithological or tectonic shielding. The crude oil of this region belong to the group of light and medium oils (with density ranging from 0.811 g/cm3 to 0.846 g/cm3). The paraffin content varies from 2.32% to 9.37% and the sulfur content from 0.45% to 0.85% on average.
Resources of developed oil fields account for 92% of total domestic resources.
Some of the fields located in the mentioned above regions contain dissolved gas components forming an oil condensate. On the Polish Lowlands the oil condensate occur mainly in Cychry and Krobielewko fields and (in less significant amounts) in Jastrzębsko, Antonin 1 and Żarnowiec W fields. On the Carpathian Foreland the oil condensate occurs in Łąkta field and in the Carpathian Mts. is co-occurring in little amounts in Słopnice field.
There are crude oil fields occurrying in Poland presented on the map.
Resources and output
The Table 1 shows resources of oil and condensate and the current state of their exploration and development.
In 2019, the exploitable resources of crude oil and condensate totaled 23,049.30 thousand tonnes (the anticipated economic and sub-economic resources in total), decreasing by 907.32 thousand tonnes in relation to the previous year. In 2019, a new field Połęcko was included into “The balance…”. It is the crude oil field accumulated in the Main Dolomite sediments with the gas cover of a minor thickness (the documented exploitable anticipated economic crude oil resources: 45.50 thousand tonnes). The most significant resources growths were recorded for Barnówko – Mostno – Buszewo field and Lubiatów field (due to the better field exploration by the ongoing exploitation and the more intensive output). The resources drops were caused mainly by the output and the resources settlement in the result of the exploitation end (Gorlice, Grabownica Wieś, Mrukowa, Rybaki and Stężyca fields).
The exploitable resources within the exploited crude oil and condensate fields amount to 21.26 million tonnes which account for 92.2% of the total domestic exploitable resources.
The economic resources of crude oil and condensate in 2019 were equal 12.95 million tonnes.
The domestic output of crude oil and condensate in 2019, from onshore and offshore fields, amounted to 936.76 thousand tonnes and decreased by 0.28 thousand tonnes in relation to the previous year. Table 2 shows the crude oil and condensate production in individual regions of the country.
The figure below shows changes in exploitable anticipated economic resources and production of oil in Poland in the years 1989-2019.
The current state of the exploration and the development together with the output amount are presented in Table 3. The fields which have been abandoned due to the exploitable resources depletion have anticipated economic or anticipated sub-economic resources documented.
The prospective resources of the crude oil in Poland, according to The balance of prospective mineral resources of Poland, are related to the oil-gas-bearing formations of the Polish Lowland (the Cambrian – about 1.1 million tonnes, the Devonian-Carboniferous – about 27.66 million tonnes, the Main Dolomite – about 235 million tonnes), on the Polish Lowland and the Carpathian Foreland (the Mesozoic – about 28.80 million tonnes), on the Carpathian Foreland and in the Carpathian Mts. (the Miocene and the its basis – about 0.6 million tonnes; the Carpathian flysch with its basis – about 124.2 million tonnes)*. The most prospective areas are the western and the eastern parts of the Carpathian Mts. with the Carpathian Foreland, the Carboniferous sediments of the north-eastern egde of the Western European platform, the western parts of the Main Dolomite platforms and the eastern part of the Fore-Sudetic Monocline. Considering the unconventional crude oil resources (the trapped crude oil), the most important areas are the compact sandstones of the Cambrian age within the Baltic basin**. The estimated crude oil resources, technically available for the exploitation, in the schists of the Lower Paleozoic age within the Baltic-Podlasie-Lublin basin in the land area, are assessed to be equal about 15.8-45.4 million tonnes, whereas in the maritime area to be equal about 73.4-99.2 million tonnes.
Prepared by: Dariusz Brzeziński, Martyna Czapigo-Czapla
* Feldman-Olszewska A., Kiersnowski H., Peryt T., Pacześna J., Laskowicz R., Janas M., Głuszyński A., Waśkiewicz K., 2020 - Ropa naftowa (crude oil), gaz ziemny (natural gas), kondensat ropno-gazowy (condensate). In: Bilans perspektywicznych zasobów kopalin Polski wg stanu na 31.12.2018 r. (eds. Szamałek K., Szuflicki M., Mizerski W.): 49-69. PIG-PIB, Warszawa.
** Wójcicki A., Kiersnowski H., Podhalańska T., Janas M., Głuszyński A., Pacześna J., Adamczak-Biały T., 2020 - Gaz i ropa z łupków (shale gas, shale oil), gaz zamknięty (tight gas). In: Bilans perspektywicznych zasobów kopalin Polski wg stanu na 31.12.2018 r. (eds. Szamałek K., Szuflicki M., Mizerski W.): 70-83. PIG-PIB, Warszawa.