We have developed a Lower Palaeozoic petroleum systems analysis in the selected zones of the Polish section of the Baltic Basin (onshore and offshore), which we carried out to assess the potential of shale rock formations as unconventional reservoirs. The areas of the Baltic Basin, which we analyzed represent a diversity of shale formations burial depths and thus different advancement of sediments compaction and organic matter transformation. Methods of dynamic petroleum systems modeling were applied with a 3D modeling workflow (PetroMod suite software). We considered an extensive array of data, including results of geochemical and petrophysical laboratory measurements, geophysical borehole data and, in selected locations — 3D seismic data. Five potentially perspective shale rock intervals (Silurian [2], Ordovician [2], and Upper Cambrian [1]) are identified and interpreted in terms of their geochemical and petrophysical properties. We calibrated the petroleum system models in terms of proper reproduction of diagenetic processes (pore pressure and porosity), thermal conditions (vitrinite reflectance, temperature), and kerogen kinetic model (organic matter transformation ratio, types of hydrocarbons generated). The results of the petroleum system simulations reveal that for the predominant part of the analyzed area, the achieved level of kerogen thermal maturity determines the generation of liquid hydrocarbons, which results in the present-day saturation of shale formations mainly with crude oil. We concluded that the highest generation yields as well as present-day hydrocarbons in place are observed for Ordovician Sasino Formation (onshore and offshore), Silurian/Llandovery Jantar member (onshore), and Upper Cambrian (alum shales) formation. Furthermore, a significant variation in the mass/volumes of accumulated hydrocarbons is observed within each of the shale formations being considered.

This paper presents the results of a research project aimed at evaluating the unconventional natural gas potential of the autochthonous Miocene sediments in the Polish part of the Carpathian Foredeep. The primary objective of the study was to re-evaluate the biogenic gas generation system within Miocene sediments, paying special attention to unconventional gas resources accumulated in tight mudstone formations. The four-dimensional (4D) petroleum system modeling method (PetroMod software) was used to reconstruct the basin geometry and three-dimensional (3D) evolution through a geological timescale, in particular the progress of gas generation, migration, and accumulation processes, as well as their consequences for gas exploration and development. Special attention was paid to the dynamics of gas generation processes and the advancement of sediment compaction and their time dependence, as well as to the progress and outcomes of gas migration and accumulation processes. The results indicate significant potential for unconventional gas accumulations in mudstone reservoirs. However, part of the biogenic gas resources occurs in a dispersed form. Analysis of the dynamics of biogenic gas generation and accumulation conducted on a basin scale and within particular sedimentary complexes and depth intervals allowed an indication of the premises regarding the most favorable zones for mudstone–claystone reservoir exploration.

The paper discusses the issue of oil-in-place estimation for liquid-saturated shales in Lower Paleozoic (Silurian and Ordovician) organic-rich formations of the Baltic Basin in North Poland. The authors adopted a geochemical method based on Rock Eval results which directly measure hydrocarbon content present in rock samples. Its application on a real data set required the implementation of correction procedures to consider also those oil compounds which were lost before Rock Eval measurements were taken or are not recorded in S1 parameter. It was accomplished through the introduction of two correction coefficients: c1—for evaporation loss and c2—for heavier compounds underestimation. The first one was approximated on the basis of published results and known properties of crude oil, while the second one was addressed with laboratory experimental procedure which combines Rock Eval pyrolysis and rock sample extraction with organic solvents. The calculation formulas were implemented in the 3D geological model of shale formations reproducing their geometry as well as the spatial variability of the petrophysical and geochemical properties. Consequently, the results of oil-in-place estimation were also available as 3D models, ready for visualization and interpretation in terms of delineation of most favorable zones or well placement. The adopted geochemical method and the results of oil-in-place estimation it produced were confronted with standard volumetric method. Although both of them are volumetric methods, the results depend on different sets of rock properties, which is an advantage for result comparison reasons. The study revealed that the geochemical method of oil-in-place estimation in liquid-rich shales after appropriate adjustment, considering shale formation and reservoir fluid dependent conditions, could provide reliable results and be implemented on the early stage of shale exploration process in a condition of production data inaccessibility.

Dynamiczne modelowanie systemów naftowych 4D w wybranych strefach basenu bałtyckiego w rozpoznawaniu złóż węglowodorów w formacjach łupkowych W artykule przedstawiono wyniki dynamicznego modelowania systemów naftowych zrealizowanego w wybranych strefach basenu bałtyckiego w kontekście rozpoznawania perspektyw poszukiwawczych w formacjach łupków sylurskich, ordowickich i górnokambryjskich. W ramach prac zintegrowano wyniki interpretacji otworowych oraz sejsmicznych, odtwarzając przestrzenne modele strukturalne i modele 3D zawartości materii organicznej (TOC). Wykorzystując informacje strukturalne, litologiczne oraz wyniki geochemicznych i petrofizycznych analiz laboratoryjnych jako dane kalibracyjne, przeprowadzono rekonstrukcję ewolucji basenu sedymentacyjnego (w sensie zmian strukturalnych oraz ewolucji parametrów formacji geologicznych) oraz symulacje przebiegu procesów naftowych. Analizie poddano efekty ewolucji basenu sedymentacyjnego i rozwoju procesów systemu naftowego w postaci: stopnia przeobrażenia substancji organicznej, czasu i intensywności procesów generacji i ekspulsji węglowo-dorów, jak również warunków dla retencji gazu lub ropy w przestrzeni porowej łupków oraz w postaci HC adsorbowanych przez kerogen obecny w formacjach łupkowych.Słowa kluczowe: systemy naftowe, basen bałtycki, formacje łupkowe, zasoby prognostyczne węglowodorów w niekonwencjonalnych złożach łupkowych. Dynamic 4D petroleum systems modeling in selected areas of the Baltic basin for exploration of unconventional shale formationsThe paper presents the results of dynamic petroleum systems modeling carried out for selected areas within the Baltic basin for the detection of exploration prospectiveness of Silurian, Ordovician and Upper Cambrian shale formations. The results of well logs and seismic data interpretation were integrated into 3D structural model and quantitative 3D model of organic content (TOC) distribution. Using structural, lithological, geochemical and petrophysical data as calibration constraints, the evolution of sedimentary basin (in the sense of structural changes and the evolution of the parameters of geological formations) was reconstructed and the simulation of petroleum processes carried out. The effects of the petroleum systems development were analyzed with respect to: organic matter transformation ratio (TR), time and intensity of generation and expulsion of hydrocarbons, the conditions for its retention in pore space of oil/gas shales, as well as in the form of hydrocarbons adsorbed by the kerogen present in the shale formations.

W artykule przedstawiono rozmieszczenie i wartości udokumentowanych zasobów geologicznych metanu w pokładach węgla (CBM) na świecie oraz dane dotyczące ich wydobycia. Scharakteryzowano warunki występowania akumulacji metanu w pokładach węgla kamiennego. Omówiono korzyści płynące z wykorzystania metanu w procesach technologiczno-produkcyjnych oraz zagrożenia związane z jego wydobyciem. Słowa kluczowe: metan z pokładów węgla, zasoby i produkcja CBM, emisja gazów cieplarnianych, gaz adsorbowany, sekwestracja, desorpcja. Coalbed methane (CBM)-global experience and the prospects of development in Poland The paper presents the distribution and value of documented coalbed methane (CBM) geological resources in the world and presents the history of the production of coaldbed gas. Conditions of the CBM accumulations occurrence were characterized. The benefits of using methane in the process of technological production-and the risks associated with its extraction were discussed.