In Poland, in 2018, there were 86 crude oil fields documented, including 29 fields situated in the Carpathian Mts., 12 on the Carpathian Foreland (in the Carpathian Foredeep), 43 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 2018, the exploitable resources of the fields located in this region accounted for 66% and the resources of the fields within the Polish economic zone of the Baltic Sea for 27% of the domestic crude oil resources in Poland. Resources of the Carpathian Foreland and the Carpathian Mts. are of a subordinate role (accounting for 4% and 3% of domestic resources, respectively).
On the Polish Lowlands, 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.
The Table 1 shows resources of oil and condensate and the current state of their exploration and development.
In 2018, exploitable resources of crude oil and condensate totaled 23,956.62 thousand tonnes (anticipated economic and sub-economic resources in total), decreasing by 37.18 thousand tonnes in relation to the previous year. In 2018, a new field Krobielewko was included into “The balance…”. It is the natural gas field with the co-occurring condensate (documented exploitable anticipated economic resources of condensate are equal 854 thousand tonnes).
The domestic output of crude oil and condensate in 2018, from onshore and offshore fields, amounted to 937.04 thousand tonnes and decreased by 2.20 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 1989-2018.
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.
Prepared by: Martyna Czapigo-Czapla, Dariusz Brzeziński