U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2012–3102

July 2012

U

Potential for Technically Recoverable Unconventional Gas and 

Oil Resources in the Polish-Ukrainian Foredeep, Poland, 2012

sing a performance-based geological assessment methodology, 

the U.S. Geological Survey estimated 

mean volumes of 1,345 billion cubic 

feet of potentially technically recoverable gas and 168 million barrels 

of technically recoverable oil and 

natural gas liquids in Ordovician and 

Silurian age shales in the PolishUkrainian Foredeep basin of Poland.

L'viv

Lublin

Warsaw

Gdansk

POLAND

DENMARK

GERMANY

SWEDEN

CZECH REPUBLIC

BELARUS

UKRAINE

LITHUANIA

RUSSIA

SLOVAKIA

BALTIC SEA

14°E 17°E 20°E 23°E 26°E 29°E

56°N

55°N

54°N

53°N

52°N

51°N

50°N

0 50 100 MILES

0 50 100 KILOMETERS

RUSSIA

TURKEY

UKRAINE

SPAIN

FRANCE

Area of

Map

EXPLANATION

Polish Foredeep Lower

 Paleozoic Oil

Polish Foredeep Lower

 Paleozoic Gas

TRANS-EUROPEAN

SUTURE

As part of a project to evaluate the poten- ZONE

tial for unconventional oil and gas resources 

in priority geological provinces worldwide, 

the U.S. Geological Survey (USGS) has assessed the potential for shale gas and shale 

oil resources in the Polish part of the PolishUkrainian Foredeep basin. Resources in the 

Ukrainian part of the basin are to be considered in a subsequent assessment.

Potentially productive organic-rich shales 

of Ordovician and Silurian age occur below 

the surface of the European Plain in a band 20 

to 200 km wide that extends from beneath the 

Baltic Sea northwest of Gdansk southeastward 

across Poland in the vicinity of Warsaw and 

Lublin and into western Ukraine near L’viv 

and beyond. Geological attributes of the shales 

are inferred from core and well log data collected in 56 wells drilled before 1990, which 

have been analyzed and interpreted by scientists of the Polish Geological Institute (PGI). 

Since 2008, additional wells have been drilled 

in the area expressly to test shale gas and shale 

oil potential. However, data and samples from 

those wells were not made available to the 

USGS for this assessment. 

Potentially productive strata range from 

tens to hundreds of meters thick, including, 

in places, almost 100 meters of black marine 

shales containing more than 2 weight percent 

total organic carbon (TOC) in type II marine 

kerogen. TOC concentrations measured in a 

few core samples are reported to exceed 9%. 

Thermal maturity of the shales with respect 

to hydrocarbon generation has been interpreted by PGI scientists (Pawel Poprawa, 

written commun., 2011) to range from therMap showing the assessed areas in the Polish part of the Polish-Ukrainian Foredeep Basin. 

The area shown in green represents the Polish Foredeep Lower Paleozoic Oil Assessment Unit. 

The area shown in red represents the Polish Foredeep Lower Paleozoic Gas Assessment Unit. 

mally immature with respect to oil generation (<0.6% vitrinite reflectance equivalent) 

in updip localities along the northeast edge 

of the basin to supermature (>3.5% vitrinite 

reflectance equivalent) along the southwest 

edge of the basin near the Trans-European 

Suture Zone. Thermal maturity information 

was used to define potentially oil productive 

and gas productive areas. However, given the 

uncertainties in data and interpretation, the 

boundary is highly uncertain. Both Upper 

Ordovician (Caradoc and Ashgill) and lower 

Silurian (Llandovery) strata are believed to 

have resource potential, but the Llandovery 

shales are considered to be more prospective.

Potentially prospective Ordovician and 

Silurian shales are parts of a sedimentary 

succession that accumulated along the southwestern edge of the East European Craton 

from latest Precambrian (Vendian) to Devonian time. The oldest strata were deposited 

in a rift-sag basin formed during the earliest 

stages of continental breakup (Poprawa and 

others, 1999). Sedimentation continued during Cambrian and Ordovician time within a 

passive margin setting after continental separation. Tectonic subsidence greatly increased 

as the continental edge changed from a passive margin to a convergent margin in the 

Middle to Late Ordovician. High rates of tectonic subsidence coupled with a global sea 

level rise during the early Silurian permitted 

sediments rich in organic carbon to accumulate near the continental margin in the newly 

formed Polish-Ukrainian Foredeep. 

Potential shale gas and shale oil reservoirs were rapidly buried beneath a thick 

accumulation of upper Silurian and Devonian strata that brought the organic-rich shales 

into temperature conditions suitable for oil 

generation. In many areas, burial was sufficient to crack the oil to natural gas. Burial 

history modeling by USGS scientists using 

data and geological interpretations provided 

by PGI suggests that oil generation in lower 

Silurian shales began at depths of about 

2,500 meters and that the oil-to-dry-gas 

Geological Model for Assessment
transition may have begun at depths of about 

3,200 m. Oil and gas generated in organicrich lower Silurian (Llandovery) shales 

and, to a lesser extent, in Upper Ordovician 

(Caradoc and Ashgill) shales occupy matrix and organic porosity in the same strata. 

These hydrocarbons, if retained in the shales, 

may constitute the principal potential unconventional petroleum resource of Poland.

Shale gas and shale oil accumulations in 

the United States were used as analogs in this 

assessment. Analog data from U.S. accumulations included mean estimated ultimate recoveries (EUR) from populations of shale gas and 

shale oil wells, mean drainage areas of directionally drilled wells, and ranges of average 

well success ratios. Principal input data used 

in the assessment are listed in table 1.

Assessment Results—Resource Summary

The USGS assessed potential technically 

recoverable shale gas and shale oil resources in the Polish sector of the Polish-Ukrainian Foredeep basin. Results of the assessment are shown in table 2. The estimated 

resources, recoverable with existing technology, range from 0 to 4,086 billion cubic 

feet of gas (BCF), with a mean estimate of 

1,345 BCF; from 0 to 172 million barrels 

of oil (MMBO), with a mean estimate of 62 

MMBO; and from 0 to 368 million barrels 

of natural gas liquids (MMBNGL), with a 

mean estimate of 106 MMBNGL. The wide 

range of resource estimates underscores the 

uncertainty inherent in this assessment. 

Further Information

 Supporting geological studies of total 

petroleum systems and assessment units, 

and reports on the methodology used in 

this assessment of the Polish sector of the 

Polish Ukrainian Foredeep are in progress. 

Complete assessment results are available 

at the USGS Energy Web site: 

http://energy.usgs.gov.

Acknowledgements

 We thank the scientists of the Polish 

Geological Institute for sharing their data 

and for educating us on the petroleum 

geology of the Polish-Ukrainian Foredeep 

prior to the assessment. Interpretations and 

collaborative geological analyses provided 

by Pawel Poprawa, then of PGI, were 

particularly helpful.

Selected References

Kanev S., Margulis, L., Bojesen-Koefoed, J.A., 

Weil, W.A., Merta, H., and Zdanaviciute, O., 

1994, Oils and hydrocarbon source rocks of 

the Baltic syneclise: Oil and Gas Journal, 

v. 92, p. 69-73.

Kowalski, A., Wiecław, D., Grotek, I., Kotarba, M.J., 

and Kosakowsk,i P., 2010, Habitat and hydrocarbon potential of the lower Paleozoic source rocks 

in the Polish part of the Baltic region: Geological 

Quarterly, v. 54, no. 2, p. 159-182.

Nehring-Lefeld, M., Modliński, Z., and Swadowska, 

E., 1997, Thermal evolution of the Ordovician 

in the western margin of the East-European 

Platform; CAI and Ro data: Geological Quarterly, 

v. 41, no. 2, p. 129-138.

Poprawa, P., Šliaupa, S., Stephenson, R.A., and 

Lazauskienê, J., 1999, Late Vendian-Early Palaeozoic tectonic evolution of the Baltic Basin; 

regional tectonic implications from subsidence 

analysis: Tectonophysics, v. 314, p. 219-239.

Assessment input data Polish Foredeep Lower Paleozoic Gas AU 

Minimum Mode Maximum Calculated mean Minimum Mode Maximum Calculated mean

Potential production area of AU (acres) 0 1,200,000 5,000,000 2,066,667 0 760,000 1,900,000 886,667

Average drainage area of wells (acres) 120 160 200 160 80 160 220 153

Average EUR (MMBO, oil; BCFG, gas) 0.1 0.2 1 0.245 0.01 0.03 0.1 0.034

Success ratios (%) 10 50 90 50 10 40 70 40

 Polish Foredeep Lower Paleozoic Oil AU

Table 1. Key assessment input data for shale gas and shale oil assessment units in Poland. 

Table 2. Assessment results for undiscovered unconventional oil and gas resources of Poland.

Polish-Ukrainian Foredeep Assessment Team: 

Donald L. Gautier, Janet K. Pitman, Ronald R. 

Charpentier, Troy Cook, Timothy R. Klett, and

Christopher J. Schenk.

Edited by Peter H. Stauffer

Graphic design by Judy Weathers

For more information, contact:

Donald L. Gautier 

(gautier@usgs.gov) 

or 

Christopher J. Schenk 

(schenk@usgs.gov)

website: http://energy.usgs.gov

This Fact Sheet and any updates to it are available 

online at:

http://pubs.usgs.gov/fs/2012/3102/

[MMBO, million barrels of oil; BCFG, billion cubic feet of gas; MMBNGL, million barrels of natural gas liquids. Results shown are fully risked estimates. For 

gas accumulations, all liquids are included as NGL (natural gas liquids) category. Undiscovered gas resources are the sum of nonassociated (gas in gas fields) and 

associated gas (gas in oil fields). F95 represents a 95 percent chance of at least the amount tabulated–other fractiles are defined similarly. Fractiles are additive under 

the assumption of perfect positive correlation. AU probability is the chance of at least one well within the AU having a production capacity of the minimum estimated 

ultimate recovery. Gray shading indicates not applicable.]

[EUR (estimated ultimate recovery per well), cell size, and success ratios are from U.S. shale gas and shale oil analogs. MMBO, million barrels of oil; BCFG, billion 

cubic feet of gas; AU, assessment unit; %, percent. Minimum, median, and maximum values represent the variation about the mean values, and do not reflect the total 

variation in these parameters. The average EUR imput is the minimum, median, maximum, and calcuated mean.]

Provinces,

Total petroleum systems (TPS), 

and Assessment Units (AU)

AU

probability

Field 

type

Total undiscovered resources

Oil (MMBO) Gas (BCFG) NGL (MMBNGL)

F95 F50 F5 Mean F95 F50 F5 Mean F95 F50 F5 Mean

TPS

Polish Foredeep Lower

Paleozoic Gas AU 0.8 Gas 0 908 3,794 1,246 0 58 347 100

Polish Foredeep Lower

Paleozoic Oil AU 0.8 Oil 0 52 172 62 0 75 292 99 0 4 21 6

Total unconventional

 resources 0 52 172 62 0 983 4,086 1,345 0 62 368 106