Diverse Anhydrous Pyrolysis Analyses for Assessment of the Hydrocarbon Generation Potential of the Dukla, Silesian, and Skole Units in the Polish Outer Carpathians

The study presents the results of investigations into various types of anhydrous pyrolysis aimed at determining the kinetic parameters of hydrocarbon generation processes from source rocks. Surface outcrop samples from the Silesian, Dukla, and Skole units, characterized by a low level of thermal maturity, were used as experimental material. The samples predominantly represented the Menilite Beds from the aforementioned three units, but also included Istebna, Lgota, Verovice, and Spas beds, which exhibit significantly lower parameters that describe generation properties. The anhydrous pyrolysis experiments provided information on the rate of organic matter decomposition (TG/DSC), the degree of conversion (Rock-Eval), the quality of the obtained products (Py/GC), and the isotopic composition of the gaseous products (Py/GC/IRMS). Chromatographic analyses confirmed the oil-prone nature of kerogen contained in the Menilites from the Dukla Unit (Tylawa area), the Silesian Unit (Iwonicz fold), and the Skole Unit, revealing an equal share of all hydrocarbon fractions: C₁–C₉, C₁₀–C₁₅, and C₁₅₊. Through the integration of pyrolytic studies conducted on potential source rocks in the polish Outer Carpathians, a new type of information was obtained regarding the rate of organic matter decomposition, as well as the fractional and isotopic composition of the pyrolysis products. The set of obtained results was used to estimate the activation energy and characterize the potential source levels. The innovative aspect of this approach involved the isotopic characterization of gaseous products generated during thermal degradation of the source rocks. These data were subsequently used to establish genetic correlations with natural gases accumulated in hydrocarbon reservoirs of the Carpathian region. It has been demonstrated that pyrolysis using PY-GC-IRMS can yield results comparable to those obtained through generation in natural geological conditions.