Geochemical assessment of liquid hydrocarbon from the Ormož-1g well (NE Slovenia)Malenšek Andolšek, Neža (Avtor) Lapanje, Andrej (Avtor) Marinović, Slavica (Avtor) Markič, Miloš (Avtor) Mura-Zala Basinhydrocarbonlight crude oilchromatographymass spectrometrybiomarkersn-alkanesthermal maturityThis study presents the results of an organic geochemical characterisation of a liquid hydrocarbon sample from the Ormož-1g well in the Mura-Zala Basin, north-eastern Slovenia. The main objective was to assess the origin, depositional environment, and thermal maturity using biomarker analysis. The bulk composition of the sample was initially determined by gas chromatography. The hydrocarbon sample was then fractionated into saturates and aromatics. These fractions were analysed by gas chromatography–mass spectrometry (GC–MS) to identify and quantify specific biomarker compounds. Based on an API gravity of 42.53° and biomarker distribution of the saturated fraction, the sample is classified as light crude oil. The dominance of high molecular weight n-alkanes and a Pr/Ph ratio of 1.83 suggests suboxic marine depositional conditions with significant terrestrial organic matter input. The sterane distribution pattern and the isoprenoid/n-alkane ratio indicate a mixed origin of organic matter. The uniform distribution of n-alkanes, a CPI value close to 1, a high degree of sterane isomerisation and the relative abundance of 3- and 2-methylphenantherene collectively indicate high thermal maturity. These establish a geochemical framework for further hydrocarbon exploration in the Mura-Zala Basin and enhance the understanding of its petroleum potential.20262026-07-06 10:53:14Neznano30807sl