The Baltic sedimentary basin contains numerous hydrocarbon fields in Lithuania. The Lower Silurian shales are considered as potential for shale gas exploration. The thickness of shale units within the oil window ranges from 115 to 180 m in west Lithuania. The average total organic carbon (TOC) content of the Lower Silurian shales is about 1.0–1.2%, with an elevated content averaging 6.7% in the Aeronian black shales. The organic matter (OM) is Type II kerogen. Pyrolysis analysis shows moderate thermal maturity parameters; Tmax is from 428 °C in central Lithuania to 455 °C in the west of the country, implying the oil generation stage. It is concluded that the burial conditions were favorable for oil generation, while the gas potential of Silurian shales is rather limited.
1. Brangulis, A. P., Kanev, S. V., Margulis, L. S., Pomerantseva, R. A. Geology and hydrocarbon prospects of the Palaeozoic in the Baltic region. In: Petroleum Geology of NW Europe. Geol. Soc. Proceedings of the 4th Conference (Parker, J. R., ed.), London, March-April, 1992, Petroleum Geology Conference series, 1993, 4, 651–656.
2. Kanev, S., Margulis, L., Bojesen-Koefoed, J. A., Weil, W. A., Merta, H., Zdanaviciute, O. Oil and hydrocarbon source rocks of the Baltic Syneclise. Oil Gas J., 1994, 92, 69–73.
3. Schleicher, M., Köster, J., Kulke, H., Weil, W. Reservoir and source-rock characterisation of the Early Palaeozoic interval in the Peribaltic Syneclise, northern Poland. J. Petrol. Geol., 1998, 21(1), 33–56.
https://doi.org/10.1111/j.1747-5457.1998.tb00645.x
4. Kowalski, A., Więcław, D., Grotek, I., Kotarba, M. J., Kosakowski, P. Habitat and hydrocarbon potential of the lower Paleozoic source rocks in the Polish part of the Baltic region. Geol. Q., 2010, 54(2), 159–182.
5. Poprawa, P., Šliaupa, S., Stephenson, R., Lazauskiene, J. Late Vendian–Early Palaeozoic tectonic evolution of the Baltic Basin: regional tectonic implications from subsidence analysis. Tectonophysics, 1999, 314(1–3), 219–239.
https://doi.org/10.1016/S0040-1951(99)00245-0
6. Poprawa, P. Shale gas potential of the Lower Palaeozoic complex in the Baltic and Lublin-Podlasie basins (Poland). Przegląd Geologiczny, 2010, 58(3), 226–249 (in Polish with English abstract).
7. Šliaupa, S., Hoth, P. Geological evolution and resources of the Baltic Sea area from the Precambrian to the Quaternary. In: The Baltic Sea Basin (Harff, J., Björck, S., Hoth, P., eds.). Springer, Berlin, 2010, 13–51.
8. Zdanavičiūtė, O., Lazauskienė, J. Organic matter of Early Silurian succession – the potential source of unconventional gas in the Baltic Basin (Lithuania). Baltica, 2009, 22(2), 89–98.
9. EIA/ARI. World Shale Gas Resources: An Initial Assessment of 14 Regions Outside the United States. US Energy Information Administration, Washington DC, 2011, 365 pp.
10. EIA/ARI. World Shale Gas and Shale Oil Resource Assessment. Prepared by Advanced Resources International, Inc., 2013, 707 pp.
11. Lazauskiene, J., Sliaupa, S., Brazauskas, A., Musteikis, P. Sequence stratigraphy of the Baltic Silurian succession: tectonic control on the foreland infill. Geological Society, London, Special Publications. 2003, 208, 95–115.
https://doi.org/10.1144/GSL.SP.2003.208.01.05
12. Paškevičius, J. The Geology of the Baltic Republics. Geological Survey of Lithuania, Vilnius, 1997.
13. Nerutshev, S. G. Handbook in Geochemistry of Oil and Gas. Nedra, 1998 (in Russian).
14. Behar, F., Beaumont, V., De B. Penteado, H. L. Rock-Eval 6 Technology: Performances and Developments. Oil Gas Sci. Technol., 2001, 56(2), 111–134.
https://doi.org/10.2516/ogst:2001013
15. Kadūnienė, E. Organic matter in oil source rocks. In: Petroleum Geology of Lithuania and Southeastern Baltic (Zdanavičiūtė, O., Sakalauskas, K., eds.). Institute of Geology, Vilnius, 2001, 96–119.
16. Schwarzkopf, T. A. Source rock potential (TOC + hydrogen index) evaluation by integrating well log and geochemical data. Org. Geochem., 1992, 19(4–6), 545–555.
https://doi.org/10.1016/0146-6380(92)90017-R
17. Passey, Q. R., Creaney, S., Kulla, J. B., Moretti, F. J., Stroud, J. D. A practical model for organic richness from porosity and resistivity logs. AAPG Bull., 1990, 74(12), 1777–1794.
18. Zdanavičiūtė, O., Swadowska, E. Petrographic and pyrolysis-gas chromatography investigations of the Early Paleozoic organic matter of Lithuania. Geologija, 2002, 40, 15–23.
19. Peters, K. E., Cassa, M. R. Applied source rock geochemistry. In: The Petroleum System – From Source to Trap (Magoon, L. B., Dow, W. G., eds.), American Association of Petroleum Geologists Memoir, Tulsa, Okla, 1994, 60, 93–120.
20. Peters, K. E., Cunningham, A. E., Walters, C. C., Jigang, J., Zhaoan, F. Petroleum systems in the Jiangling-Dangyang area, Jianghan Basin, China. Org. Geochem., 1996, 24(10–11), 1035–1060.
https://doi.org/10.1016/S0146-6380(96)00080-0
21. Peters, K. E., Walters, C. C., Moldowan, J. M. The Biomarker Guide. Biomarkers and Isotopes in Petroleum Systems and Earth History, V. 2. United Kingdom, Cambridge University Press, 2005.
22. Zdanavičiūtė, O., Lazauskienė, J. The petroleum potential of the Silurian succession in Lithuania. J. Petrol. Geol., 2007, 30(4), 325–337.
https://doi.org/10.1111/j.1747-5457.2007.00325.x
23. Horsfield, B., Schulz, H.-M., GASH Team. GASH: A shale gas initiative for Europe. EGU General Assembly. Geophysical Research Abstracts, 2008, 10, EGU2008-A-01508.
24. Zdanavičiūtė, O. E. Chemical characteristics of oils and variations in their composition. In: Petroleum Geology of Lithuania and Southeastern Baltic (Zdanavičiūtė, O., Sakalauskas, K., eds.). Institute of Geology, Vilnius, 2001, 131–147.
25. Kiersnowski, H., Dyrka, I. Ordovician-Silurian shale gas resources potential in Poland: evaluation of Gas Resources Assessment Reports published to date and expected improvements for 2014 forthcoming Assessment. Przegląd Geologiczny, 2013, 61(11/1), 639–656 (in Polish with English abstract).
